1
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Meng Z, Stolz RM, De Moraes LS, Jones CG, Eagleton AM, Nelson HM, Mirica KA. Gas-Induced Electrical and Magnetic Modulation of Two-Dimensional Conductive Metal-Organic Framework. Angew Chem Int Ed Engl 2024:e202404290. [PMID: 38589297 DOI: 10.1002/anie.202404290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 04/03/2024] [Accepted: 04/04/2024] [Indexed: 04/10/2024]
Abstract
Controlled modulation of electronic and magnetic properties in stimuli-responsive materials provides valuable insights for the design of magnetoelectric or multiferroic devices. This paper demonstrates the modulation of electrical and magnetic properties of a semiconductive, paramagnetic metal-organic framework Cu3(C6O6)2 with small gaseous molecules, NH3, H2S, and NO. This study merges chemiresistive and magnetic tests to reveal that the MOF undergoes simultaneous changes in electrical conductance and magnetization that are uniquely modulated by each gas. The features of response, including direction, magnitude, and kinetics, are modulated by the physicochemical properties of the gaseous molecules. This study advances the design of multifunctional materials capable of undergoing simultaneous changes in electrical and magnetic properties in response to chemical stimuli.
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Affiliation(s)
- Zheng Meng
- Dartmouth College, Chemistry, UNITED STATES
| | | | | | | | | | - Hosea M Nelson
- California Institute of Technology, Chemistry, UNITED STATES
| | - Katherine A Mirica
- Dartmouth College, Chemistry, 41 College Street, Burke 214, 03755, Hanover, UNITED STATES
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2
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Zhao Z, Popov S, Lee W, Burch JE, Delgadillo DA, Kim LJ, Shahgholi M, Lebrón-Acosta N, Houk KN, Nelson HM. Accessing Medium-Sized Rings via Vinyl Carbocation Intermediates. Org Lett 2024; 26:1000-1005. [PMID: 38295154 PMCID: PMC10863392 DOI: 10.1021/acs.orglett.3c04014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 12/11/2023] [Accepted: 12/19/2023] [Indexed: 02/02/2024]
Abstract
Medium-sized rings (8-11-membered cycles) are often more challenging to synthesize than smaller rings (5-7-membered cycles) due to ring strain. Herein, we report a catalytic method for forming 8- and 9-membered rings that proceeds via the intramolecular Friedel-Crafts reactions of vinyl carbocation intermediates. These reactive species are generated catalytically through the ionization of vinyl toluenesulfonates by a Lewis acidic lithium cation-weakly coordinating anion salt.
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Affiliation(s)
- Zhenqi Zhao
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
| | - Stasik Popov
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, Los Angeles, California 90095, United States
| | - Woojin Lee
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, Los Angeles, California 90095, United States
| | - Jessica E. Burch
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
| | - David A. Delgadillo
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
| | - Lee Joon Kim
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, Los Angeles, California 90095, United States
| | - Mona Shahgholi
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
| | - Naiara Lebrón-Acosta
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
| | - K. N. Houk
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, Los Angeles, California 90095, United States
| | - Hosea M. Nelson
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
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3
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Delgadillo D, Burch JE, Kim LJ, de Moraes LS, Niwa K, Williams J, Tang MJ, Lavallo VG, Khatri Chhetri B, Jones CG, Rodriguez IH, Signore JA, Marquez L, Bhanushali R, Woo S, Kubanek J, Quave C, Tang Y, Nelson HM. High-Throughput Identification of Crystalline Natural Products from Crude Extracts Enabled by Microarray Technology and microED. ACS Cent Sci 2024; 10:176-183. [PMID: 38292598 PMCID: PMC10823509 DOI: 10.1021/acscentsci.3c01365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 12/04/2023] [Accepted: 12/04/2023] [Indexed: 02/01/2024]
Abstract
The structural determination of natural products (NPs) can be arduous because of sample heterogeneity. This often demands iterative purification processes and characterization of complex molecules that may be available only in miniscule quantities. Microcrystal electron diffraction (microED) has recently shown promise as a method to solve crystal structures of NPs from nanogram quantities of analyte. However, its implementation in NP discovery remains hampered by sample throughput and purity requirements, akin to traditional NP-discovery workflows. In the methods described herein, we leverage the resolving power of transmission electron microscopy (TEM) and the miniaturization capabilities of deoxyribonucleic acid (DNA) microarray technology to address these challenges through the establishment of an NP screening platform, array electron diffraction (ArrayED). In this workflow, an array of high-performance liquid chromatography (HPLC) fractions taken from crude extracts was deposited onto TEM grids in picoliter-sized droplets. This multiplexing of analytes on TEM grids enables 1200 or more unique samples to be simultaneously inserted into a TEM instrument equipped with an autoloader. Selected area electron diffraction analysis of these microarrayed grids allows for the rapid identification of crystalline metabolites. In this study, ArrayED enabled structural characterization of 14 natural products, including four novel crystal structures and two novel polymorphs, from 20 crude extracts. Moreover, we identify several chemical species that would not be detected by standard mass spectrometry (MS) or ultraviolet-visible (UV/vis) spectroscopy and crystal forms that would not be characterized using traditional methods.
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Affiliation(s)
- David
A. Delgadillo
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
| | - Jessica E. Burch
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
| | - Lee Joon Kim
- Department of Chemistry
and Biochemistry, and Department of Chemical and Biomolecular
Engineering, University of California, Los
Angeles, Los Angeles, California 90095, United States
| | - Lygia S. de Moraes
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
| | - Kanji Niwa
- Department of Chemistry
and Biochemistry, and Department of Chemical and Biomolecular
Engineering, University of California, Los
Angeles, Los Angeles, California 90095, United States
| | - Jason Williams
- Department of Chemistry
and Biochemistry, and Department of Chemical and Biomolecular
Engineering, University of California, Los
Angeles, Los Angeles, California 90095, United States
| | - Melody J. Tang
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
| | - Vincent G. Lavallo
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
| | - Bhuwan Khatri Chhetri
- School
of Biological Sciences, School of Chemistry
and Biochemistry, and Neuroscience Program, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Christopher G. Jones
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
| | - Isabel Hernandez Rodriguez
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
| | - Joshua A. Signore
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
| | - Lewis Marquez
- Molecular
and Systems Pharmacology, Laney Graduate School, Emory University, Atlanta, Georgia 30322, United States
| | - Riya Bhanushali
- School
of Biological Sciences, School of Chemistry
and Biochemistry, and Neuroscience Program, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Sunmin Woo
- Center
for the Study of Human Health, Emory University, Atlanta, Georgia 30322, United States
| | - Julia Kubanek
- School
of Biological Sciences, School of Chemistry
and Biochemistry, and Neuroscience Program, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Cassandra Quave
- Molecular
and Systems Pharmacology, Laney Graduate School, Emory University, Atlanta, Georgia 30322, United States
- Center
for the Study of Human Health, Emory University, Atlanta, Georgia 30322, United States
- Department
of Dermatology, Emory University School
of Medicine, Atlanta, Georgia 30322, United
States
| | - Yi Tang
- Department of Chemistry
and Biochemistry, and Department of Chemical and Biomolecular
Engineering, University of California, Los
Angeles, Los Angeles, California 90095, United States
| | - Hosea M. Nelson
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
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4
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Lin SY, Oakley CE, Jenkinson CB, Chiang YM, Lee CK, Jones CG, Seidler PM, Nelson HM, Todd RB, Wang CCC, Oakley BR. A heterologous expression platform in Aspergillus nidulans for the elucidation of cryptic secondary metabolism biosynthetic gene clusters: discovery of the Aspergillus fumigatus sartorypyrone biosynthetic pathway. Chem Sci 2023; 14:11022-11032. [PMID: 37860661 PMCID: PMC10583710 DOI: 10.1039/d3sc02226a] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 06/26/2023] [Indexed: 10/21/2023] Open
Abstract
Aspergillus fumigatus is a serious human pathogen causing life-threatening Aspergillosis in immunocompromised patients. Secondary metabolites (SMs) play an important role in pathogenesis, but the products of many SM biosynthetic gene clusters (BGCs) remain unknown. In this study, we have developed a heterologous expression platform in Aspergillus nidulans, using a newly created genetic dereplication strain, to express a previously unknown BGC from A. fumigatus and determine its products. The BGC produces sartorypyrones, and we have named it the spy BGC. Analysis of targeted gene deletions by HRESIMS, NMR, and microcrystal electron diffraction (MicroED) enabled us to identify 12 products from the spy BGC. Seven of the compounds have not been isolated previously. We also individually expressed the polyketide synthase (PKS) gene spyA and demonstrated that it produces the polyketide triacetic acid lactone (TAL), a potentially important biorenewable platform chemical. Our data have allowed us to propose a biosynthetic pathway for sartorypyrones and related natural products. This work highlights the potential of using the A. nidulans heterologous expression platform to uncover cryptic BGCs from A. fumigatus and other species, despite the complexity of their secondary metabolomes.
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Affiliation(s)
- Shu-Yi Lin
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California Los Angeles CA 90089 USA
| | - C Elizabeth Oakley
- Department of Molecular Biosciences, University of Kansas 1200 Sunnyside Avenue Lawrence KS 66045 USA
| | - Cory B Jenkinson
- Department of Molecular Biosciences, University of Kansas 1200 Sunnyside Avenue Lawrence KS 66045 USA
| | - Yi-Ming Chiang
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California Los Angeles CA 90089 USA
| | - Ching-Kuo Lee
- School of Pharmacy, College of Pharmacy, Taipei Medical University Taipei 11031 Taiwan
| | - Christopher G Jones
- The Arnold and Mabel Beckman Laboratory of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology Pasadena California 91125 USA
| | - Paul M Seidler
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California Los Angeles CA 90089 USA
| | - Hosea M Nelson
- The Arnold and Mabel Beckman Laboratory of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology Pasadena California 91125 USA
| | - Richard B Todd
- Department of Plant Pathology, Kansas State University Manhattan KS 66506 USA
| | - Clay C C Wang
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California Los Angeles CA 90089 USA
- Department of Chemistry, University of Southern California Los Angeles CA 90089 USA
| | - Berl R Oakley
- Department of Molecular Biosciences, University of Kansas 1200 Sunnyside Avenue Lawrence KS 66045 USA
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5
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Williams CG, Nistanaki SK, Wells CW, Nelson HM. α-Vinylation of Ester Equivalents via Main Group Catalysis for the Construction of Quaternary Centers. Org Lett 2023; 25:3591-3595. [PMID: 37192420 DOI: 10.1021/acs.orglett.3c00535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
A methodology for the construction of sterically congested quaternary centers via the trapping of vinyl carbocations with silyl ketene acetals is disclosed. This main group-catalyzed α-vinylation reaction is advantageous as methods to access these congested motifs are limited. Moreover, β,γ-unsaturated carbonyl moieties and tetrasubstituted alkenes are present in various bioactive natural products and pharmaceuticals, and this catalytic platform offers a means of accessing them using simple and inexpensive materials.
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Affiliation(s)
- Chloe G Williams
- Department of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Sepand K Nistanaki
- Department of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Conner W Wells
- Department of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Hosea M Nelson
- Department of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
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6
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Khatri Chhetri B, Mojib N, Moore SG, Delgadillo DA, Burch JE, Barrett NH, Gaul DA, Marquez L, Soapi K, Nelson HM, Quave CL, Kubanek J. Cryptic Chemical Variation in a Marine Red Alga as Revealed by Nontargeted Metabolomics. ACS Omega 2023; 8:13899-13910. [PMID: 37091395 PMCID: PMC10116502 DOI: 10.1021/acsomega.3c00301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Accepted: 03/29/2023] [Indexed: 05/03/2023]
Abstract
Many marine algae occupy habitats that are dark, deep, or encrusted on other organisms and hence are frequently overlooked by natural product chemists. However, exploration of less-studied organisms can lead to new opportunities for drug discovery. Genetic variation at the individual, species, genus, and population levels as well as environmental influences on gene expression enable expansion of the chemical repertoire associated with a taxonomic group, enabling natural product exploration using innovative analytical methods. A nontargeted LC-MS and 1H NMR spectroscopy-based metabolomic study of 32 collections of representatives of the calcareous red algal genus Peyssonnelia from coral reef habitats in Fiji and the Solomon Islands revealed significant correlations between natural products' chemistry, phylogeny, and biomedically relevant biological activity. Hierarchical cluster analysis (HCA) of LC-MS data in conjunction with NMR profiling and MS/MS-based molecular networking revealed the presence of at least four distinct algal chemotypes within the genus Peyssonnelia. Two Fijian collections were prioritized for further analysis, leading to the isolation of three novel sulfated triterpene glycosides with a rearranged isomalabaricane carbon skeleton, guided by the metabolomic data. The discovery of peyssobaricanosides A-C (15-17) from two Fijian Peyssonnelia collections, but not from closely related specimens collected in the Solomon Islands that were otherwise chemically and phylogenetically very similar, alludes to population-level variation in secondary metabolite production. Our study reinforces the significance of exploring unusual ecological niches and showcases marine red algae as a chemically rich treasure trove.
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Affiliation(s)
- Bhuwan Khatri Chhetri
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia 30332, United States
- Center
for Microbial Dynamics and Infection, Georgia
Institute of Technology, Atlanta, Georgia 30332, United States
| | - Nazia Mojib
- Department
of Biology, Spelman College, Atlanta, Georgia 30314, United States
| | - Samuel G. Moore
- Parker
H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - David A. Delgadillo
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
| | - Jessica E. Burch
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
| | - Nolan H. Barrett
- School
of Earth and Atmospheric Sciences, Atlanta, Georgia 30332, United States
| | - David A. Gaul
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia 30332, United States
- Parker
H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Lewis Marquez
- Department
of Dermatology, Center for the Study of Human Health, and Antibiotic
Resistance Center, Emory University, Atlanta, Georgia 30322, United States
| | - Katy Soapi
- Institute
of Applied Sciences, University of South
Pacific, Suva, Fiji
| | - Hosea M. Nelson
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
| | - Cassandra L. Quave
- Department
of Dermatology, Center for the Study of Human Health, and Antibiotic
Resistance Center, Emory University, Atlanta, Georgia 30322, United States
| | - Julia Kubanek
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia 30332, United States
- Center
for Microbial Dynamics and Infection, Georgia
Institute of Technology, Atlanta, Georgia 30332, United States
- School
of Biological Sciences, Georgia Institute
of Technology, Atlanta, Georgia 30332, United States
- Parker
H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
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7
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Lee W, Nelson HM, Houk KN. Computational Exploration of the Nature of Li +-Ureide Anion Catalysis on Formation of Highly Reactive Vinyl Carbocations and Subsequent C-C Bond Forming Reactions. J Org Chem 2023; 88:3403-3408. [PMID: 36820472 DOI: 10.1021/acs.joc.2c02178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
The mechanisms of the C-H insertion reactions of vinyl carbocations formed by heterolysis of vinyl trifluoromethanesulfonates (triflates) by catalytic lithiated 1,3-bis[3,5-bis(trifluoromethyl)phenyl]urea (Li+-ureide) have been studied with ωB97X-D density functional theory. The ionization promoted by the Li+-ureide forms a metastable intimate ion pair complex of Li+-ureide-triflate anion and vinyl cation. The relative thermodynamic stabilities of isomeric alkyl cations are impacted by ion-pairing with the Li+-ureide-triflate anion. We show that the C-H insertion reaction of the vinyl cation intermediate is the rate-determining step and explain the effect of the aryl substituents on the formation of the vinyl cation and its C-H insertion reactivity as well as the regioselectivity of C-H activation by the vinyl cation.
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Affiliation(s)
- Woojin Lee
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Hosea M Nelson
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - K N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
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8
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Romero EO, Perkins JC, Burch JE, Delgadillo DA, Nelson HM, Narayan ARH. Chemoenzymatic Synthesis of (+)-Xyloketal B. Org Lett 2023; 25:1547-1552. [PMID: 36827601 DOI: 10.1021/acs.orglett.3c00334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
Xyloketal B is a pentacyclic fungal marine natural product that has shown potential for the treatment of diseases such as Alzheimer's disease and atherosclerosis. Herein, we describe the first asymmetric synthesis of this natural product, which relies on a chemoenzymatic strategy. This approach leverages a biocatalytic benzylic hydroxylation to access to an ortho-quinone methide intermediate which is captured in a [4 + 2] cycloaddition to stereoselectively yield a key cyclic ketal intermediate enroute to (+)-xyloketal B. The relative configuration of this intermediate was rapidly confirmed as the desired stereoisomer using MicroED. To complete the synthesis, a second ortho-quinone methide was accessed through a reductive approach, ultimately leading to the stereoselective synthesis of (+)-xyloketal B.
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Affiliation(s)
- Evan O Romero
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States.,Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Jonathan C Perkins
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States.,Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Jessica E Burch
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - David A Delgadillo
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Hosea M Nelson
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Alison R H Narayan
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States.,Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States.,Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48109, United States
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9
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Nistanaki SK, Williams CG, Wigman B, Wong JJ, Haas BC, Popov S, Werth J, Sigman MS, Houk KN, Nelson HM. Catalytic asymmetric C-H insertion reactions of vinyl carbocations. Science 2022; 378:1085-1091. [PMID: 36480623 PMCID: PMC9993429 DOI: 10.1126/science.ade5320] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
From the preparation of pharmaceuticals to enzymatic construction of natural products, carbocations are central to molecular synthesis. Although these reactive intermediates are engaged in stereoselective processes in nature, exerting enantiocontrol over carbocations with synthetic catalysts remains challenging. Many resonance-stabilized tricoordinated carbocations, such as iminium and oxocarbenium ions, have been applied in catalytic enantioselective reactions. However, their dicoordinated counterparts (aryl and vinyl carbocations) have not, despite their emerging utility in chemical synthesis. We report the discovery of a highly enantioselective vinyl carbocation carbon-hydrogen (C-H) insertion reaction enabled by imidodiphosphorimidate organocatalysts. Active site confinement featured in this catalyst class not only enables effective enantiocontrol but also expands the scope of vinyl cation C-H insertion chemistry, which broadens the utility of this transition metal-free C(sp3)-H functionalization platform.
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Affiliation(s)
- Sepand K Nistanaki
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Chloe G Williams
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Benjamin Wigman
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Jonathan J Wong
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Brittany C Haas
- Department of Chemistry, University of Utah, Salt Lake City, UT 84112, USA
| | - Stasik Popov
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Jacob Werth
- Department of Chemistry, University of Utah, Salt Lake City, UT 84112, USA
| | - Matthew S Sigman
- Department of Chemistry, University of Utah, Salt Lake City, UT 84112, USA
| | - K N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Hosea M Nelson
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
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10
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Hui C, Schmollinger S, Strenkert D, Holbrook K, Montgomery HR, Chen S, Nelson HM, Weber PK, Merchant SS. Simple steps to enable reproducibility: culture conditions affecting Chlamydomonas growth and elemental composition. Plant J 2022; 111:995-1014. [PMID: 35699388 DOI: 10.1111/tpj.15867] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 06/01/2022] [Accepted: 06/03/2022] [Indexed: 05/26/2023]
Abstract
Even subtle modifications in growth conditions elicit acclimation responses affecting the molecular and elemental makeup of organisms, both in the laboratory and in natural habitats. We systematically explored the effect of temperature, pH, nutrient availability, culture density, and access to CO2 and O2 in laboratory-grown algal cultures on growth rate, the ionome, and the ability to accumulate Fe. We found algal cells accumulate Fe in alkaline conditions, even more so when excess Fe is present, coinciding with a reduced growth rate. Using a combination of Fe-specific dyes, X-ray fluorescence microscopy, and NanoSIMS, we show that the alkaline-accumulated Fe was intracellularly sequestered into acidocalcisomes, which are localized towards the periphery of the cells. At high photon flux densities, Zn and Ca specifically over-accumulate, while Zn alone accumulates at low temperatures. The impact of aeration was probed by reducing shaking speeds and changing vessel fill levels; the former increased the Cu quota of cultures, the latter resulted in a reduction in P, Ca, and Mn at low fill levels. Trace element quotas were also affected in the stationary phase, where specifically Fe, Cu, and Zn accumulate. Cu accumulation here depends inversely on the Fe concentration of the medium. Individual laboratory strains accumulate Ca, P, and Cu to different levels. All together, we identified a set of specific changes to growth rate, elemental composition, and the capacity to store Fe in response to subtle differences in culturing conditions of Chlamydomonas, affecting experimental reproducibility. Accordingly, we recommend that these variables be recorded and reported as associated metadata.
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Affiliation(s)
- Colleen Hui
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA
- Chemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, CA, 94550, USA
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA, 94720, USA
| | - Stefan Schmollinger
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA, 94720, USA
| | - Daniela Strenkert
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA, 94720, USA
| | - Kristen Holbrook
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA
| | - Hayden R Montgomery
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA
| | - Si Chen
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Hosea M Nelson
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA
| | - Peter K Weber
- Lawrence Livermore National Laboratory, Physical and Life Science Directorate, Livermore, CA, 94550, USA
| | - Sabeeha S Merchant
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA, 94720, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720, USA
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, 94720, USA
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11
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Lovera SO, Bagdasarian AL, Guo J, Nelson HM, Lavallo V. Correction: Cesium carbonate mediated C-H functionalization of perhalogenated 12-vertex carborane anions. Chem Commun (Camb) 2022; 58:6558. [PMID: 35605976 PMCID: PMC9157083 DOI: 10.1039/d2cc90180c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Correction for ‘Cesium carbonate mediated C–H functionalization of perhalogenated 12-vertex carborane anions’ by Sergio O. Lovera et al., Chem. Commun., 2022, 58, 4060–4062, DOI: https://doi.org/10.1039/D2CC00173J.
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Affiliation(s)
- Sergio O Lovera
- Departments of Chemistry, University of California Riverside, Riverside, CA 92521, USA.
| | - Alex L Bagdasarian
- Department of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
| | - Juchen Guo
- Department of Chemical and Environmental Engineering, University of California Riverside, Riverside, CA 92521, USA.
| | - Hosea M Nelson
- Department of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
| | - Vincent Lavallo
- Departments of Chemistry, University of California Riverside, Riverside, CA 92521, USA.
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12
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Wigman B, Lee W, Wei W, Houk KN, Nelson HM. Electrochemical Fluorination of Vinyl Boronates through Donor-Stabilized Vinyl Carbocation Intermediates. Angew Chem Int Ed Engl 2022; 61:e202113972. [PMID: 35029844 PMCID: PMC8901537 DOI: 10.1002/anie.202113972] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Indexed: 01/24/2023]
Abstract
The electrochemical generation of vinyl carbocations from alkenyl boronic esters and boronates is reported. Using easy-to-handle nucleophilic fluoride reagents, these intermediates are trapped to form fully substituted vinyl fluorides. Mechanistic studies support the formation of dicoordinated carbocations through sequential single-electron oxidation events. Notably, this electrochemical fluorination features fast reaction times and Lewis acid-free conditions. This transformation provides a complementary method to access vinyl fluorides with simple fluoride salts such as TBAF.
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Affiliation(s)
- Benjamin Wigman
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Woojin Lee
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Wenjing Wei
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Kendall N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Hosea M Nelson
- Department of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
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13
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Wigman B, Lee W, Wei W, Houk KN, Nelson HM. Electrochemical Fluorination of Vinyl Boronates through Donor‐Stabilized Vinyl Carbocation Intermediates**. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202113972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Benjamin Wigman
- Department of Chemistry and Biochemistry University of California, Los Angeles Los Angeles CA 90095 USA
| | - Woojin Lee
- Department of Chemistry and Biochemistry University of California, Los Angeles Los Angeles CA 90095 USA
| | - Wenjing Wei
- Department of Chemistry and Biochemistry University of California, Los Angeles Los Angeles CA 90095 USA
| | - Kendall N. Houk
- Department of Chemistry and Biochemistry University of California, Los Angeles Los Angeles CA 90095 USA
| | - Hosea M. Nelson
- Department of Chemistry and Chemical Engineering California Institute of Technology Pasadena CA 91125 USA
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14
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Meng Z, Jones CG, Farid S, Khan IU, Nelson HM, Mirica KA. Unraveling the Electrical and Magnetic Properties of Layered Conductive Metal‐Organic Framework With Atomic Precision. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202113569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Zheng Meng
- Department of Chemistry Dartmouth College Burke Laboratory Hanover NH 03755 USA
| | - Christopher G. Jones
- The Arnold and Mabel Beckman Laboratory of Chemical Synthesis Division of Chemistry and Chemical Engineering California Institute of Technology Pasadena CA 91125 USA
| | - Sidra Farid
- Material Chemistry Laboratory Department of Chemistry GC University Lahore 54000 Pakistan
| | - Islam Ullah Khan
- Material Chemistry Laboratory Department of Chemistry GC University Lahore 54000 Pakistan
- Department of Chemistry University of Mianwali Mianwali 42200 Pakistan
| | - Hosea M. Nelson
- The Arnold and Mabel Beckman Laboratory of Chemical Synthesis Division of Chemistry and Chemical Engineering California Institute of Technology Pasadena CA 91125 USA
| | - Katherine A. Mirica
- Department of Chemistry Dartmouth College Burke Laboratory Hanover NH 03755 USA
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15
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Lovera SO, Bagsdasarian AL, Guo J, Nelson HM, Lavallo V. Cesium carbonate mediated C–H functionalization of perhalogenated 12-vertex carborane anions. Chem Commun (Camb) 2022; 58:4060-4062. [DOI: 10.1039/d2cc00173j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
C–H functionalization of undecahalogenated carborane anions, [HCB11X11−] (X = Cl, Br, I), is performed with Cs2CO3 in acetonitrile.
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Affiliation(s)
- Sergio O. Lovera
- Departments of Chemistry, University of California Riverside, Riverside, CA 92521, USA
| | | | - Juchen Guo
- Department of Chemical and Environmental Engineering, University of California Riverside, Riverside, CA 92521, USA
| | - Hosea M. Nelson
- Department of Chemistry and Chemical Engineering, Pasadena, CA 91125, USA
| | - Vincent Lavallo
- Departments of Chemistry, University of California Riverside, Riverside, CA 92521, USA
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16
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Aykanat A, Jones CG, Cline E, Stolz RM, Meng Z, Nelson HM, Mirica KA. Conductive Stimuli-Responsive Coordination Network Linked with Bismuth for Chemiresistive Gas Sensing. ACS Appl Mater Interfaces 2021; 13:60306-60318. [PMID: 34898182 PMCID: PMC9201806 DOI: 10.1021/acsami.1c14453] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
This paper describes the design, synthesis, characterization, and performance of a novel semiconductive crystalline coordination network, synthesized using 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP) ligands interconnected with bismuth ions, toward chemiresistive gas sensing. Bi(HHTP) exhibits two distinct structures upon hydration and dehydration of the pores within the network, Bi(HHTP)-α and Bi(HHTP)-β, respectively, both with unprecedented network topology (2,3-c and 3,4,4,5-c nodal net stoichiometry, respectively) and unique corrugated coordination geometries of HHTP molecules held together by bismuth ions, as revealed by a crystal structure resolved via microelectron diffraction (MicroED) (1.00 Å resolution). Good electrical conductivity (5.3 × 10-3 S·cm-1) promotes the utility of this material in the chemical sensing of gases (NH3 and NO) and volatile organic compounds (VOCs: acetone, ethanol, methanol, and isopropanol). The chemiresistive sensing of NO and NH3 using Bi(HHTP) exhibits limits of detection 0.15 and 0.29 parts per million (ppm), respectively, at low driving voltages (0.1-1.0 V) and operation at room temperature. This material is also capable of exhibiting unique and distinct responses to VOCs at ppm concentrations. Spectroscopic assessment via X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopic methods (i.e., attenuated total reflectance-infrared spectroscopy (ATR-IR) and diffuse reflectance infrared Fourier transformed spectroscopy (DRIFTS)), suggests that the sensing mechanisms of Bi(HHTP) to VOCs, NO, and NH3 comprise a complex combination of steric, electronic, and protic properties of the targeted analytes.
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Affiliation(s)
- Aylin Aykanat
- Department
of Chemistry, Burke Laboratory, Dartmouth
College, Hanover, New Hampshire 03755, United States
| | - Christopher G. Jones
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
| | - Evan Cline
- Department
of Chemistry, Burke Laboratory, Dartmouth
College, Hanover, New Hampshire 03755, United States
| | - Robert M. Stolz
- Department
of Chemistry, Burke Laboratory, Dartmouth
College, Hanover, New Hampshire 03755, United States
| | - Zheng Meng
- Department
of Chemistry, Burke Laboratory, Dartmouth
College, Hanover, New Hampshire 03755, United States
| | - Hosea M. Nelson
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
| | - Katherine A. Mirica
- Department
of Chemistry, Burke Laboratory, Dartmouth
College, Hanover, New Hampshire 03755, United States
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17
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Anderson CL, Li H, Jones CG, Teat SJ, Settineri NS, Dailing EA, Liang J, Mao H, Yang C, Klivansky LM, Li X, Reimer JA, Nelson HM, Liu Y. Solution-processable and functionalizable ultra-high molecular weight polymers via topochemical synthesis. Nat Commun 2021; 12:6818. [PMID: 34819494 PMCID: PMC8613210 DOI: 10.1038/s41467-021-27090-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 11/01/2021] [Indexed: 01/25/2023] Open
Abstract
Topochemical polymerization reactions hold the promise of producing ultra-high molecular weight crystalline polymers. However, the totality of topochemical polymerization reactions has failed to produce ultra-high molecular weight polymers that are both soluble and display variable functionality, which are restrained by the crystal-packing and reactivity requirements on their respective monomers in the solid state. Herein, we demonstrate the topochemical polymerization reaction of a family of para-azaquinodimethane compounds that undergo facile visible light and thermally initiated polymerization in the solid state, allowing for the first determination of a topochemical polymer crystal structure resolved via the cryoelectron microscopy technique of microcrystal electron diffraction. The topochemical polymerization reaction also displays excellent functional group tolerance, accommodating both solubilizing side chains and reactive groups that allow for post-polymerization functionalization. The thus-produced soluble ultra-high molecular weight polymers display superior capacitive energy storage properties. This study overcomes several synthetic and characterization challenges amongst topochemical polymerization reactions, representing a critical step toward their broader application.
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Affiliation(s)
- Christopher L Anderson
- The Molecular Foundry, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA, 94720, USA
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - He Li
- The Molecular Foundry, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA, 94720, USA
| | - Christopher G Jones
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Simon J Teat
- Advanced Light Source, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA, 94720, USA
| | - Nicholas S Settineri
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, 94720, USA
- Advanced Light Source, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA, 94720, USA
| | - Eric A Dailing
- The Molecular Foundry, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA, 94720, USA
| | - Jiatao Liang
- The Molecular Foundry, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA, 94720, USA
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Haiyan Mao
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Chongqing Yang
- The Molecular Foundry, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA, 94720, USA
| | - Liana M Klivansky
- The Molecular Foundry, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA, 94720, USA
| | - Xinle Li
- The Molecular Foundry, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA, 94720, USA
| | - Jeffrey A Reimer
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Hosea M Nelson
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
| | - Yi Liu
- The Molecular Foundry, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA, 94720, USA.
- Materials Sciences Division, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA, 94720, USA.
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18
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Meng Z, Jones CG, Farid S, Khan IU, Nelson HM, Mirica KA. Unraveling the Electrical and Magnetic Properties of Layered Conductive Metal-Organic Framework With Atomic Precision. Angew Chem Int Ed Engl 2021; 61:e202113569. [PMID: 34784436 DOI: 10.1002/anie.202113569] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Indexed: 12/16/2022]
Abstract
This paper describes structural elucidation of a layered conductive metal-organic framework (MOF) material Cu3 (C6 O6 )2 by microcrystal electron diffraction with sub-angstrom precision. This insight enables the first identification of an unusual π-stacking interaction in a layered MOF material characterized by an extremely short (2.73 Å) close packing of the ligand arising from pancake bonding and ordered water clusters within pores. Band structure analysis suggests semiconductive properties of the MOF, which are likely related to the localized nature of pancake bonds and the formation of a singlet dimer of the ligand. The spin of CuII within the Kagomé arrangement dominates the paramagnetism of the MOF, leading to strong geometrical magnetic frustration.
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Affiliation(s)
- Zheng Meng
- Department of Chemistry, Dartmouth College, Burke Laboratory, Hanover, NH, 03755, USA
| | - Christopher G Jones
- The Arnold and Mabel Beckman Laboratory of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Sidra Farid
- Material Chemistry Laboratory, Department of Chemistry, GC University, Lahore, 54000, Pakistan
| | - Islam Ullah Khan
- Material Chemistry Laboratory, Department of Chemistry, GC University, Lahore, 54000, Pakistan.,Department of Chemistry, University of Mianwali, Mianwali, 42200, Pakistan
| | - Hosea M Nelson
- The Arnold and Mabel Beckman Laboratory of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Katherine A Mirica
- Department of Chemistry, Dartmouth College, Burke Laboratory, Hanover, NH, 03755, USA
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19
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Abstract
4-Hydroxy-2-pyridone alkaloids have attracted attention for synthetic and biosynthetic studies due to their broad biological activities and structural diversity. Here, we elucidated the pathway and chemical logic of (-)-sambutoxin (1) biosynthesis. In particular, we uncovered the enzymatic origin of the tetrahydropyran moiety and showed that the p-hydroxyphenyl group is installed via a late-stage, P450-catalyzed oxidation of the phenylalanine-derived side chain rather than via a direct incorporation of tyrosine.
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Affiliation(s)
- Eun Bin Go
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Lee Joon Kim
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Hosea M Nelson
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
- Department of Chemistry, California Institute of Technology, Pasadena, California 91125, United States
| | - Masao Ohashi
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California 90095, United States
| | - Yi Tang
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California 90095, United States
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20
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Kim LJ, Ohashi M, Zhang Z, Tan D, Asay M, Cascio D, Rodriguez JA, Tang Y, Nelson HM. Prospecting for natural products by genome mining and microcrystal electron diffraction. Nat Chem Biol 2021; 17:872-877. [PMID: 34312563 DOI: 10.1038/s41589-021-00834-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 06/14/2021] [Indexed: 11/09/2022]
Abstract
More than 60% of pharmaceuticals are related to natural products (NPs), chemicals produced by living organisms. Despite this, the rate of NP discovery has slowed over the past few decades. In many cases the rate-limiting step in NP discovery is structural characterization. Here we report the use of microcrystal electron diffraction (MicroED), an emerging cryogenic electron microscopy (CryoEM) method, in combination with genome mining to accelerate NP discovery and structural elucidation. As proof of principle we rapidly determine the structure of a new 2-pyridone NP, Py-469, and revise the structure of fischerin, an NP isolated more than 25 years ago, with potent cytotoxicity but hitherto ambiguous structural assignment. This study serves as a powerful demonstration of the synergy of MicroED and synthetic biology in NP discovery, technologies that when taken together will ultimately accelerate the rate at which new drugs are discovered.
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Affiliation(s)
- Lee Joon Kim
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA
| | - Masao Ohashi
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, CA, USA
| | - Zhuan Zhang
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, CA, USA
| | - Dan Tan
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, CA, USA
| | - Matthew Asay
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA
| | - Duilio Cascio
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA.,UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles, Los Angeles, CA, USA
| | - José A Rodriguez
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA.,UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles, Los Angeles, CA, USA
| | - Yi Tang
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA. .,Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, CA, USA.
| | - Hosea M Nelson
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA.
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21
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Jellen MJ, Liepuoniute I, Jin M, Jones CG, Yang S, Jiang X, Nelson HM, Houk KN, Garcia-Garibay MA. Enhanced Gearing Fidelity Achieved Through Macrocyclization of a Solvated Molecular Spur Gear. J Am Chem Soc 2021; 143:7740-7747. [PMID: 33998231 DOI: 10.1021/jacs.1c01885] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Molecular spur gear dynamics with high gearing fidelity can be achieved through a careful selection of constituent molecular components that favorably position and maintain the two gears in a meshed configuration. Here, we report the synthesis of a new macrocyclic molecular spur gear with a bibenzimidazole stator combined with a second naphthyl bis-gold-phosphine gold complex stator to place two 3-fold symmetric 9,10-diethynyl triptycene cogs at the optimal distance of 8.1 Å for gearing. Micro electron diffraction (μED) analysis confirmed the formation of the macrocyclic structure and the proper alignment of the triptycene cogs. Gearing dynamics in solution are predicted to be extremely fast and, in fact, were too fast to be observed with variable-temperature 1H NMR using CD2Cl2 as the solvent. A combination of molecular dynamics and metadynamics simulations predict that the barriers for gearing and slippage are ca. 4 kcal mol-1 and ca. 9 kcal mol-1, respectively. This system is characterized by enhanced gearing fidelity compared to the acyclic analog. This is achieved by rigidification of the structure, locking the two triptycenes in the preferred gearing distance and orientation.
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Affiliation(s)
- Marcus J Jellen
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Ieva Liepuoniute
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Mingoo Jin
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Christopher G Jones
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Song Yang
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Xing Jiang
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Hosea M Nelson
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - K N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Miguel A Garcia-Garibay
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
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22
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Affiliation(s)
- Lee Joon Kim
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Mengzhao Xue
- Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
| | - Xin Li
- Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
| | - Zhi Xu
- Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
| | - Eric Paulson
- Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
- Chemical and Biological Instrumentation Center, Yale University, New Haven, Connecticut 06511, United States
| | - Brandon Mercado
- Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
- Chemical and Biological Instrumentation Center, Yale University, New Haven, Connecticut 06511, United States
| | - Hosea M. Nelson
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Seth B. Herzon
- Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
- Department of Pharmacology, Yale School of Medicine, New Haven, Connecticut 06510, United States
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23
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Samkian AE, Kiel GR, Jones CG, Bergman HM, Oktawiec J, Nelson HM, Tilley TD. Elucidation of Diverse Solid-State Packing in a Family of Electron-Deficient Expanded Helicenes via Microcrystal Electron Diffraction (MicroED)*. Angew Chem Int Ed Engl 2021; 60:2493-2499. [PMID: 33090649 DOI: 10.1002/anie.202012213] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Indexed: 02/02/2023]
Abstract
Solid-state packing plays a defining role in the properties of a molecular organic material, but it is difficult to elucidate in the absence of single crystals that are suitable for X-ray diffraction. Herein, we demonstrate the coupling of divergent synthesis with microcrystal electron diffraction (MicroED) for rapid assessment of solid-state packing motifs, using a class of chiral nanocarbons-expanded helicenes-as a proof of concept. Two highly selective oxidative dearomatizations of a readily accessible helicene provided a divergent route to four electron-deficient analogues containing quinone or quinoxaline units. Crystallization efforts consistently yielded microcrystals that were unsuitable for single-crystal X-ray diffraction, but ideal for MicroED. This technique facilitated the elucidation of solid-state structures of all five compounds with <1.1 Å resolution. The otherwise-inaccessible data revealed a range of notable packing behaviors, including four different space groups, homochirality in a crystal for a helicene with an extremely low enantiomerization barrier, and nanometer scale cavities.
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Affiliation(s)
- Adrian E Samkian
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Gavin R Kiel
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Christopher G Jones
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Harrison M Bergman
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Julia Oktawiec
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Hosea M Nelson
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - T Don Tilley
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, 94720, USA
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24
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Nelson HM, Siu JC, Saha A, Cascio D, MacMillan SN, Wu SB, Lu C, Rodríguez JA, Houk KN, Lin S. Isolation and X-ray Crystal Structure of an Electrogenerated TEMPO–N3 Charge-Transfer Complex. Org Lett 2021; 23:454-458. [DOI: 10.1021/acs.orglett.0c03966] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hosea M. Nelson
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Juno C. Siu
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Ambarneil Saha
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Duilio Cascio
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
- UCLA-DOE Institute for Genomics & Proteomics, University of California, Los Angeles, California 90095, United States
| | - Samantha N. MacMillan
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Song-Bai Wu
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
- Shenzhen Grubbs Institute and Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China
| | - Chenxi Lu
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - José A. Rodríguez
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
- UCLA-DOE Institute for Genomics & Proteomics, University of California, Los Angeles, California 90095, United States
| | - K. N. Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Song Lin
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
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25
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Nelson HM, Popov S, Shao B, Bagdasarian AL, Wigman B. C–H Functionalization Reactions of Phenyl and Vinyl Carbocations Paired with Weakly Coordinating Anions. Synlett 2020. [DOI: 10.1055/s-0040-1707908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Carbocations have played a central role in the chemical sciences for over a century. In a synthetic setting, most methods utilize stabilized tricoordinate carbocations, while there are far fewer examples of reactions featuring nonstabilized dicoordinate cations. Here, we provide an overview of recent developments in the generation of high-energy carbocations mediated by weakly coordinating anions and the C–H insertion reactions of such carbocations. Moreover, we discuss mechanistic studies of these catalytic C–H insertion reactions aimed at furthering our understanding of the reactive nature of these rarely invoked cationic intermediates.1 Introduction2 Background: Phenyl Carbocations3 Silylium/Carborane-Catalyzed C–H Insertion Reactions of Phenyl Carbocations4 Silane-Fueled, Weakly Coordinating Anion-Catalyzed, Reductive C–H Insertion Reactions of Vinyl Carbocations5 C–H Insertion Reactivity of Vinyl Carbocations under Basic Conditions6 Conclusion and Outlook
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Affiliation(s)
- Hosea M. Nelson
- Department of Chemistry and Biochemistry, University of California
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26
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Samkian AE, Kiel GR, Jones CG, Bergman HM, Oktawiec J, Nelson HM, Tilley TD. Elucidation of Diverse Solid‐State Packing in a Family of Electron‐Deficient Expanded Helicenes via Microcrystal Electron Diffraction (MicroED)**. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202012213] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Adrian E. Samkian
- Department of Chemistry University of California, Berkeley Berkeley CA 94720 USA
| | - Gavin R. Kiel
- Department of Chemistry University of California, Berkeley Berkeley CA 94720 USA
| | - Christopher G. Jones
- Department of Chemistry and Biochemistry University of California, Los Angeles Los Angeles CA 90095 USA
| | - Harrison M. Bergman
- Department of Chemistry University of California, Berkeley Berkeley CA 94720 USA
| | - Julia Oktawiec
- Department of Chemistry University of California, Berkeley Berkeley CA 94720 USA
| | - Hosea M. Nelson
- Department of Chemistry and Biochemistry University of California, Los Angeles Los Angeles CA 90095 USA
| | - T. Don Tilley
- Department of Chemistry University of California, Berkeley Berkeley CA 94720 USA
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27
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Bagdasarian AL, Popov S, Wigman B, Wei W, Lee W, Nelson HM. Urea-Catalyzed Vinyl Carbocation Formation Enables Mild Functionalization of Unactivated C-H Bonds. Org Lett 2020; 22:7775-7779. [PMID: 32558583 DOI: 10.1021/acs.orglett.0c01745] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Herein we report the 3,5-bistrifluoromethylphenyl urea-catalyzed functionalization of unactivated C-H bonds. In this system, the urea catalyst mediates the formation of high-energy vinyl carbocations that undergo facile C-H insertion and Friedel-Crafts reactions. We introduce a new paradigm for these privileged scaffolds where the combination of hydrogen-bonding motifs and strong bases affords highly active Lewis acid catalysts capable of ionizing strong C-O bonds. Despite the highly Lewis-acidic nature of these catalysts that enables triflate abstraction from sp2 carbons, these newly found reaction conditions allow for the formation of heterocycles and tolerate highly Lewis-basic heteroaromatic substrates. This strategy showcases the potential utility of dicoordinated vinyl carbocations in organic synthesis.
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Affiliation(s)
- Alex L Bagdasarian
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Stasik Popov
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Benjamin Wigman
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Wenjing Wei
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Woojin Lee
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Hosea M Nelson
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
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28
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Curtis BJ, Kim LJ, Wrobel CJJ, Eagan JM, Smith RA, Burch JE, Le HH, Artyukhin AB, Nelson HM, Schroeder FC. Identification of Uric Acid Gluconucleoside-Ascaroside Conjugates in Caenorhabditis elegans by Combining Synthesis and MicroED. Org Lett 2020; 22:6724-6728. [PMID: 32820938 PMCID: PMC7526323 DOI: 10.1021/acs.orglett.0c02038] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Few nucleoside-derived natural products have been identified from animals, despite the ubiquity of nucleosides in living organisms. Here, we use a combination of synthesis and the emerging electron microscopy technique microcrystal electron diffraction to determine the structures of several N3-(β-glucopyranosyl)uric acid derivatives in Caenorhabditis elegans. These noncanonical gluconucleosides further integrate an ascaroside moiety, for which we present a shortened synthetic route. The production of a phosphorylated gluconucleoside is influenced by evolutionarily conserved insulin signaling.
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Affiliation(s)
- Brian J Curtis
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Lee Joon Kim
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Chester J J Wrobel
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - James M Eagan
- Ascribe Bioscience, Ithaca, New York 14853, United States
| | - Rubin A Smith
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Jessica E Burch
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Henry H Le
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Alexander B Artyukhin
- Chemistry Department, College of Environmental Science and Forestry, State University of New York, Syracuse, New York 13210, United States
| | - Hosea M Nelson
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Frank C Schroeder
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
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29
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Abstract
We report the utility of readily available heterocycles as precursors to unique ring-opening metathesis polymerization (ROMP) monomers. Photochemical valence isomerization reactions of pyridones, dihydropyridines, and pyrones dearomatize the parent heterocycles to their highly strained Dewar isomers, which readily engage in controlled ROMP reactions using Grubbs catalysts. This strategy is used to access polymer backbones that contain strained β-lactam and azetidine cores, which can be further derivatized using post-polymerization chemistries. We demonstrate this through the synthesis of water-soluble β-amino acid polymers that have potential applications as biomedical materials, along with the synthesis of highly-soluble poly(acetylene) derivatives, which have potential applications as organic conductive materials derived from bio-feedstock chemicals.
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Affiliation(s)
- Sepand K Nistanaki
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Hosea M Nelson
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
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30
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Shao B, Bagdasarian AL, Popov S, Nelson HM. Intermolecular C–H Insertion of Aryl Cations. Trends in Chemistry 2019. [DOI: 10.1016/j.trechm.2019.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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31
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Green SA, Montgomery HR, Benton TR, Chan NJ, Nelson HM. Regulating Transition-Metal Catalysis through Interference by Short RNAs. Angew Chem Int Ed Engl 2019; 58:16400-16404. [PMID: 31313425 DOI: 10.1002/anie.201905333] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 06/24/2019] [Indexed: 12/14/2022]
Abstract
Herein we report the discovery of a AuI -DNA hybrid catalyst that is compatible with biological media and whose reactivity can be regulated by small complementary nucleic acid sequences. The development of this catalytic system was enabled by the discovery of a novel AuI -mediated base pair. We found that AuI binds DNA containing C-T mismatches. In the AuI -DNA catalyst's latent state, the AuI ion is sequestered by the mismatch such that it is coordinatively saturated, rendering it catalytically inactive. Upon addition of an RNA or DNA strand that is complementary to the latent catalyst's oligonucleotide backbone, catalytic activity is induced, leading to a sevenfold increase in the formation of a fluorescent product, forged through a AuI -catalyzed hydroamination reaction. Further development of this catalytic system will expand not only the chemical space available to synthetic biological systems but also allow for temporal and spatial control of transition-metal catalysis through gene transcription.
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Affiliation(s)
- Sydnee A Green
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Hayden R Montgomery
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Tyler R Benton
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Neil J Chan
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Hosea M Nelson
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, 90095, USA
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32
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Green SA, Montgomery HR, Benton TR, Chan NJ, Nelson HM. Regulating Transition‐Metal Catalysis through Interference by Short RNAs. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201905333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Sydnee A. Green
- Department of Chemistry and Biochemistry University of California, Los Angeles Los Angeles CA 90095 USA
| | - Hayden R. Montgomery
- Department of Chemistry and Biochemistry University of California, Los Angeles Los Angeles CA 90095 USA
| | - Tyler R. Benton
- Department of Chemistry and Biochemistry University of California, Los Angeles Los Angeles CA 90095 USA
| | - Neil J. Chan
- Department of Chemistry and Biochemistry University of California, Los Angeles Los Angeles CA 90095 USA
| | - Hosea M. Nelson
- Department of Chemistry and Biochemistry University of California, Los Angeles Los Angeles CA 90095 USA
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33
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Jones CG, Asay M, Kim LJ, Kleinsasser JF, Saha A, Fulton TJ, Berkley KR, Cascio D, Malyutin AG, Conley MP, Stoltz BM, Lavallo V, Rodríguez JA, Nelson HM. Characterization of Reactive Organometallic Species via MicroED. ACS Cent Sci 2019; 5:1507-1513. [PMID: 31572777 PMCID: PMC6764211 DOI: 10.1021/acscentsci.9b00403] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Indexed: 06/10/2023]
Abstract
Here we apply microcrystal electron diffraction (MicroED) to the structural determination of transition-metal complexes. We find that the simultaneous use of 300 keV electrons, very low electron doses, and an ultrasensitive camera allows for the collection of data without cryogenic cooling of the stage. This technique reveals the first crystal structures of the classic zirconocene hydride, colloquially known as "Schwartz's reagent", a novel Pd(II) complex not amenable to solution-state NMR or X-ray crystallography, and five other paramagnetic and diamagnetic transition-metal complexes.
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Affiliation(s)
- Christopher G. Jones
- Department of Chemistry and Biochemistry and
UCLA-DOE Institute for Genomics & Proteomics,
University of California, Los Angeles, California 90095,
United States
| | - Matthew Asay
- Department of Chemistry and Biochemistry and
UCLA-DOE Institute for Genomics & Proteomics,
University of California, Los Angeles, California 90095,
United States
| | - Lee Joon Kim
- Department of Chemistry and Biochemistry and
UCLA-DOE Institute for Genomics & Proteomics,
University of California, Los Angeles, California 90095,
United States
| | - Jack F. Kleinsasser
- Department of Chemistry, University of
California, Riverside, California 92521, United
States
| | - Ambarneil Saha
- Department of Chemistry and Biochemistry and
UCLA-DOE Institute for Genomics & Proteomics,
University of California, Los Angeles, California 90095,
United States
| | - Tyler J. Fulton
- The Warren and Katharine Schlinger Laboratory for
Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering and
Beckman Institute, California Institute of
Technology, Pasadena, California 91125, United
States
| | - Kevin R. Berkley
- Department of Chemistry, University of
California, Riverside, California 92521, United
States
| | - Duilio Cascio
- Department of Chemistry and Biochemistry and
UCLA-DOE Institute for Genomics & Proteomics,
University of California, Los Angeles, California 90095,
United States
| | - Andrey G. Malyutin
- The Warren and Katharine Schlinger Laboratory for
Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering and
Beckman Institute, California Institute of
Technology, Pasadena, California 91125, United
States
| | - Matthew P. Conley
- Department of Chemistry, University of
California, Riverside, California 92521, United
States
| | - Brian M. Stoltz
- The Warren and Katharine Schlinger Laboratory for
Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering and
Beckman Institute, California Institute of
Technology, Pasadena, California 91125, United
States
| | - Vincent Lavallo
- Department of Chemistry, University of
California, Riverside, California 92521, United
States
| | - José A. Rodríguez
- Department of Chemistry and Biochemistry and
UCLA-DOE Institute for Genomics & Proteomics,
University of California, Los Angeles, California 90095,
United States
| | - Hosea M. Nelson
- Department of Chemistry and Biochemistry and
UCLA-DOE Institute for Genomics & Proteomics,
University of California, Los Angeles, California 90095,
United States
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34
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Wigman B, Popov S, Bagdasarian AL, Shao B, Benton TR, Williams CG, Fisher SP, Lavallo V, Houk KN, Nelson HM. Vinyl Carbocations Generated under Basic Conditions and Their Intramolecular C-H Insertion Reactions. J Am Chem Soc 2019; 141:9140-9144. [PMID: 31082208 DOI: 10.1021/jacs.9b02110] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Here we report the surprising discovery that high-energy vinyl carbocations can be generated under strongly basic conditions, and that they engage in intramolecular sp3 C-H insertion reactions through the catalysis of weakly coordinating anion salts. This approach relies on the unconventional combination of lithium hexamethyldisilazide base and the commercially available catalyst, triphenylmethylium tetrakis(pentafluorophenyl)borate. These reagents form a catalytically active lithium species that enables the application of vinyl cation C-H insertion reactions to heteroatom-containing substrates.
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Affiliation(s)
- Benjamin Wigman
- Department of Chemistry and Biochemistry , University of California , Los Angeles , California 90095 , United States
| | - Stasik Popov
- Department of Chemistry and Biochemistry , University of California , Los Angeles , California 90095 , United States
| | - Alex L Bagdasarian
- Department of Chemistry and Biochemistry , University of California , Los Angeles , California 90095 , United States
| | - Brian Shao
- Department of Chemistry and Biochemistry , University of California , Los Angeles , California 90095 , United States
| | - Tyler R Benton
- Department of Chemistry and Biochemistry , University of California , Los Angeles , California 90095 , United States
| | - Chloé G Williams
- Department of Chemistry and Biochemistry , University of California , Los Angeles , California 90095 , United States
| | - Steven P Fisher
- Department of Chemistry , University of California , Riverside , California 92521 , United States
| | - Vincent Lavallo
- Department of Chemistry , University of California , Riverside , California 92521 , United States
| | - K N Houk
- Department of Chemistry and Biochemistry , University of California , Los Angeles , California 90095 , United States
| | - Hosea M Nelson
- Department of Chemistry and Biochemistry , University of California , Los Angeles , California 90095 , United States
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35
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Fisher SP, Tomich AW, Lovera SO, Kleinsasser JF, Guo J, Asay MJ, Nelson HM, Lavallo V. Nonclassical Applications of closo-Carborane Anions: From Main Group Chemistry and Catalysis to Energy Storage. Chem Rev 2019; 119:8262-8290. [PMID: 30707011 DOI: 10.1021/acs.chemrev.8b00551] [Citation(s) in RCA: 173] [Impact Index Per Article: 34.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Classically closo-carborane anions, particularly [HCB11H11]- and [HCB9H9]-, and their derivatives have primarily been used as weakly coordinating anions to isolate reactive intermediates, platforms for stoichiometric and catalytic functionalization, counteranions for simple Lewis acid catalysis, and components of materials like liquid crystals. The aim of this article is to educate the reader on the contemporary nonclassical applications of these anions. Specifically, this review will cover new directions in main group catalysis utilized to achieve some of the most challenging catalytic reactions such as C-F, C-H, and C-C functionalizations that are difficult or impossible to realize with transition metals. In addition, the review will cover the utilization of the clusters as dianionic C σ-bound ligands for coordination chemistry, ligand substituents for coordination chemistry and advanced catalyst design, and covalently bound spectator substituents to stabilize radicals. Furthermore, their applications as solution-based and solid-state electrolytes for Li, Na, and Mg batteries will be discussed.
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Affiliation(s)
- S P Fisher
- Department of Chemistry , University of California, Riverside , 501 Big Springs Road , Riverside , California 92521 , United States
| | - A W Tomich
- Department of Chemistry , University of California, Riverside , 501 Big Springs Road , Riverside , California 92521 , United States
| | - S O Lovera
- Department of Chemistry , University of California, Riverside , 501 Big Springs Road , Riverside , California 92521 , United States
| | - J F Kleinsasser
- Department of Chemistry , University of California, Riverside , 501 Big Springs Road , Riverside , California 92521 , United States
| | - J Guo
- Department of Chemical and Environmental Engineering , University of California, Riverside , Riverside , California 92521 , United States
| | - M J Asay
- Department of Chemistry and Biochemistry , University of California , Los Angeles , California 90095 , United States
| | - H M Nelson
- Department of Chemistry and Biochemistry , University of California , Los Angeles , California 90095 , United States
| | - V Lavallo
- Department of Chemistry , University of California, Riverside , 501 Big Springs Road , Riverside , California 92521 , United States
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36
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Abstract
Disclosed is a five-step synthesis of (±)-vibralactone, a biologically active terpenoid natural product. A key photochemical valence isomerization of 3-prenyl-pyran-2-one produces both the all-carbon quaternary stereocenter and the β-lactone at an early stage. Cyclopropanation of the resulting bicyclic β-lactone produces a strained housane structure that is converted to the natural product through a sequential ring expansion and reduction strategy. This concise and modular route to the natural product provides the shortest total synthesis of (±)-vibralactone reported to date.
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Affiliation(s)
- Sepand K Nistanaki
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Luke A Boralsky
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Roy D Pan
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Hosea M Nelson
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, 90095, USA
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37
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Affiliation(s)
- Sepand K. Nistanaki
- Department of Chemistry and BiochemistryUniversity of California, Los Angeles Los Angeles CA 90095 USA
| | - Luke A. Boralsky
- Department of Chemistry and BiochemistryUniversity of California, Los Angeles Los Angeles CA 90095 USA
| | - Roy D. Pan
- Department of Chemistry and BiochemistryUniversity of California, Los Angeles Los Angeles CA 90095 USA
| | - Hosea M. Nelson
- Department of Chemistry and BiochemistryUniversity of California, Los Angeles Los Angeles CA 90095 USA
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38
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Jones C, Martynowycz MW, Hattne J, Fulton TJ, Stoltz BM, Rodriguez JA, Nelson HM, Gonen T. The CryoEM Method MicroED as a Powerful Tool for Small Molecule Structure Determination. ACS Cent Sci 2018; 4:1587-1592. [PMID: 30555912 PMCID: PMC6276044 DOI: 10.1021/acscentsci.8b00760] [Citation(s) in RCA: 216] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Indexed: 05/20/2023]
Abstract
In the many scientific endeavors that are driven by organic chemistry, unambiguous identification of small molecules is of paramount importance. Over the past 50 years, NMR and other powerful spectroscopic techniques have been developed to address this challenge. While almost all of these techniques rely on inference of connectivity, the unambiguous determination of a small molecule's structure requires X-ray and/or neutron diffraction studies. In practice, however, X-ray crystallography is rarely applied in routine organic chemistry due to intrinsic limitations of both the analytes and the technique. Here we report the use of the electron cryo-microscopy (cryoEM) method microcrystal electron diffraction (MicroED) to provide routine and unambiguous structural determination of small organic molecules. From simple powders, with minimal sample preparation, we could collect high-quality MicroED data from nanocrystals (∼100 nm, ∼10-15 g) resulting in atomic resolution (<1 Å) crystal structures in minutes.
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Affiliation(s)
- Christopher
G. Jones
- Department of Chemistry and Biochemistry, Howard Hughes Medical Institute,
David Geffen School of Medicine, Departments of Biological Chemistry
and Physiology, and UCLA-DOE Institute, University of California, Los Angeles, California 90095, United States
| | - Michael W. Martynowycz
- Department of Chemistry and Biochemistry, Howard Hughes Medical Institute,
David Geffen School of Medicine, Departments of Biological Chemistry
and Physiology, and UCLA-DOE Institute, University of California, Los Angeles, California 90095, United States
| | - Johan Hattne
- Department of Chemistry and Biochemistry, Howard Hughes Medical Institute,
David Geffen School of Medicine, Departments of Biological Chemistry
and Physiology, and UCLA-DOE Institute, University of California, Los Angeles, California 90095, United States
| | - Tyler J. Fulton
- The
Warren and Katharine Schlinger Laboratory of Chemistry and Chemical
Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Brian M. Stoltz
- The
Warren and Katharine Schlinger Laboratory of Chemistry and Chemical
Engineering, California Institute of Technology, Pasadena, California 91125, United States
- (B.M.S.) E-mail:
| | - Jose A. Rodriguez
- Department of Chemistry and Biochemistry, Howard Hughes Medical Institute,
David Geffen School of Medicine, Departments of Biological Chemistry
and Physiology, and UCLA-DOE Institute, University of California, Los Angeles, California 90095, United States
- (J.A.R.) E-mail:
| | - Hosea M. Nelson
- Department of Chemistry and Biochemistry, Howard Hughes Medical Institute,
David Geffen School of Medicine, Departments of Biological Chemistry
and Physiology, and UCLA-DOE Institute, University of California, Los Angeles, California 90095, United States
- (H.M.N.) E-mail:
| | - Tamir Gonen
- Department of Chemistry and Biochemistry, Howard Hughes Medical Institute,
David Geffen School of Medicine, Departments of Biological Chemistry
and Physiology, and UCLA-DOE Institute, University of California, Los Angeles, California 90095, United States
- (T.G.) E-mail:
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39
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Popov S, Shao B, Bagdasarian AL, Benton TR, Zou L, Yang Z, Houk KN, Nelson HM. Teaching an old carbocation new tricks: Intermolecular C-H insertion reactions of vinyl cations. Science 2018; 361:381-387. [PMID: 30049877 DOI: 10.1126/science.aat5440] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 06/05/2018] [Indexed: 11/02/2022]
Abstract
Vinyl carbocations have been the subject of extensive experimental and theoretical studies over the past five decades. Despite this long history in chemistry, the utility of vinyl cations in chemical synthesis has been limited, with most reactivity studies focusing on solvolysis reactions or intramolecular processes. Here we report synthetic and mechanistic studies of vinyl cations generated through silylium-weakly coordinating anion catalysis. We find that these reactive intermediates undergo mild intermolecular carbon-carbon bond-forming reactions, including carbon-hydrogen (C-H) insertion into unactivated sp3 C-H bonds and reductive Friedel-Crafts reactions with arenes. Moreover, we conducted computational studies of these alkane C-H functionalization reactions and discovered that they proceed through nonclassical, ambimodal transition structures. This reaction manifold provides a framework for the catalytic functionalization of hydrocarbons using simple ketone derivatives.
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Affiliation(s)
- Stasik Popov
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Brian Shao
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Alex L Bagdasarian
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Tyler R Benton
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Luyi Zou
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA.,Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, People's Republic of China
| | - Zhongyue Yang
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - K N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Hosea M Nelson
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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40
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Avila CM, Patel JS, Reddi Y, Saito M, Nelson HM, Shunatona HP, Sigman MS, Sunoj RB, Toste FD. Enantioselective Heck-Matsuda Arylations through Chiral Anion Phase-Transfer of Aryl Diazonium Salts. Angew Chem Int Ed Engl 2017; 56:5806-5811. [PMID: 28418118 PMCID: PMC5528849 DOI: 10.1002/anie.201702107] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Revised: 03/26/2017] [Indexed: 11/10/2022]
Abstract
A mild, asymmetric Heck-Matsuda reaction of five-, six- and seven-membered ring alkenes and aryl diazonium salts is presented. High yields and enantioselectivities were achieved using Pd0 and chiral anion co-catalysts, the latter functioning as a chiral anion phase-transfer (CAPT) reagent. For certain substrate classes, the chiral anion catalysts were modulated to minimize the formation of undesired by-products. More specifically, BINAM-derived phosphoric acid catalysts were shown to prevent alkene isomerization in cyclopentene and cycloheptene starting materials. DFT(B3LYP-D3) computations revealed that increased product selectivity resulted from a chiral anion dependent lowering of the activation barrier for the desired pathway.
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Affiliation(s)
- Carolina M Avila
- Department of Chemistry, University of California, Berkeley, CA, 94720, USA
| | - Jigar S Patel
- Department of Chemistry, University of California, Berkeley, CA, 94720, USA
| | - Yernaidu Reddi
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Masato Saito
- Department of Chemistry, University of California, Berkeley, CA, 94720, USA
| | - Hosea M Nelson
- Department of Chemistry, University of California, Berkeley, CA, 94720, USA
- Current address: Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095-1569, USA
| | - Hunter P Shunatona
- Department of Chemistry, University of California, Berkeley, CA, 94720, USA
| | - Matthew S Sigman
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, UT, 84112, USA
| | - Raghavan B Sunoj
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - F Dean Toste
- Department of Chemistry, University of California, Berkeley, CA, 94720, USA
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Avila CM, Patel JS, Reddi Y, Saito M, Nelson HM, Shunatona HP, Sigman MS, Sunoj RB, Toste FD. Enantioselective Heck-Matsuda Arylations through Chiral Anion Phase-Transfer of Aryl Diazonium Salts. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201702107] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Carolina M. Avila
- Department of Chemistry; University of California; Berkeley CA 94720 USA
| | - Jigar S. Patel
- Department of Chemistry; University of California; Berkeley CA 94720 USA
| | - Yernaidu Reddi
- Department of Chemistry; Indian Institute of Technology Bombay; Powai Mumbai 400076 India
| | - Masato Saito
- Department of Chemistry; University of California; Berkeley CA 94720 USA
| | - Hosea M. Nelson
- Department of Chemistry; University of California; Berkeley CA 94720 USA
- Current address: Department of Chemistry and Biochemistry; University of California; Los Angeles CA 90095-1569 USA
| | | | - Matthew S. Sigman
- Department of Chemistry; University of Utah; 315 South 1400 East Salt Lake City UT 84112 USA
| | - Raghavan B. Sunoj
- Department of Chemistry; Indian Institute of Technology Bombay; Powai Mumbai 400076 India
| | - F. Dean Toste
- Department of Chemistry; University of California; Berkeley CA 94720 USA
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Shao B, Bagdasarian AL, Popov S, Nelson HM. Arylation of hydrocarbons enabled by organosilicon reagents and weakly coordinating anions. Science 2017; 355:1403-1407. [DOI: 10.1126/science.aam7975] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 03/09/2017] [Indexed: 11/02/2022]
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Nelson HM, Williams BD, Miró J, Toste FD. Enantioselective 1,1-arylborylation of alkenes: merging chiral anion phase transfer with Pd catalysis. J Am Chem Soc 2015; 137:3213-3216. [PMID: 25723255 DOI: 10.1021/jacs.5b00344] [Citation(s) in RCA: 126] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A palladium-catalyzed three-component coupling of α-olefins, aryldiazonium salts, and bis(pinacolato)diboron affords direct access to chiral benzylic boronic esters. This process is rendered highly enantioselective using an unprecedented example of cooperative chiral anion phase transfer and transition-metal catalysis.
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Affiliation(s)
- Hosea M Nelson
- Department of Chemistry, University of California, Berkeley, California 94720, United States; Chemical Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Brett D Williams
- Department of Chemistry, University of California, Berkeley, California 94720, United States; Chemical Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Javier Miró
- Department of Chemistry, University of California, Berkeley, California 94720, United States; Chemical Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - F Dean Toste
- Department of Chemistry, University of California, Berkeley, California 94720, United States; Chemical Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
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Abstract
The enantioselective amination of carbonyl derivatives is achieved via phase-transfer of aryldiazonium salts by BINAM-derived phosphoric acids.
Chiral anion phase-transfer of aryldiazonium cations was utilized to achieve highly enantioselective α-amination of carbonyl compounds. A broad scope of indanone- and benzosuberone-derived substrates was amenable to this strategy. Critical to obtaining high levels of enantioselectivity was the use of BINAM-derived phosphoric acids. The utility of this transformation was demonstrated through facile conversion of diazene products to valuable α-amino acid derivatives.
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Affiliation(s)
- H M Nelson
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - J S Patel
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - H P Shunatona
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - F D Toste
- Department of Chemistry, University of California, Berkeley, California 94720, United States
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Gordon JR, Nelson HM, Virgil SC, Stoltz BM. The total syntheses of basiliolide C, epi-basiliolide C, and protecting-group-free total syntheses of transtaganolides C and D. J Org Chem 2014; 79:9740-7. [PMID: 25244187 DOI: 10.1021/jo501924u] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The total syntheses of basiliolide C and previously unreported epi-basiliolide C are achieved by an Ireland-Claisen/Diels-Alder cascade. The development of a palladium catalyzed cross-coupling of methoxy alkynyl zinc reagents allows for the protecting-group-free syntheses of transtaganolides C and D. Syntheses of transtaganolides C and D are accomplished in a single operation to generate three rings, two all-carbon quaternary centers, and four tertiary stereocenters from a monocyclic, achiral precursor.
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Affiliation(s)
- Jonny R Gordon
- Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology , 1200 East California Boulevard, MC 101-20, Pasadena, California 91125, United States
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Nelson HM, Reisberg SH, Shunatona HP, Patel JS, Toste FD. Chiral anion phase transfer of aryldiazonium cations: an enantioselective synthesis of C3-diazenated pyrroloindolines. Angew Chem Int Ed Engl 2014; 53:5600-3. [PMID: 24715416 DOI: 10.1002/anie.201310905] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 02/17/2014] [Indexed: 11/09/2022]
Abstract
Herein is reported the first asymmetric utilization of aryldiazonium cations as a source of electrophilic nitrogen. This is achieved through a chiral anion phase-transfer pyrroloindolinization reaction that forms C3-diazenated pyrroloindolines from simple tryptamines and aryldiazonium tetrafluoroborates. The title compounds are obtained in up to 99% yield and 96% ee. The air- and water-tolerant reaction allows electronic and steric diversity of the aryldiazonium electrophile and the tryptamine core.
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Affiliation(s)
- Hosea M Nelson
- Department of Chemistry, University of California at Berkeley, Latimer Hall, Berkeley, CA (USA)
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Nelson HM, Reisberg SH, Shunatona HP, Patel JS, Toste FD. Chiral Anion Phase Transfer of Aryldiazonium Cations: An Enantioselective Synthesis of C3-Diazenated Pyrroloindolines. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201310905] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Abstract
Nucleic acid probes are used for diverse applications in vitro, in situ, and in vivo. In any setting, their power is limited by imperfect selectivity (binding of undesired targets) and incomplete affinity (binding is reversible, and not all desired targets bound). These difficulties are fundamental, stemming from reliance on base pairing to provide both selectivity and affinity. Shielded covalent (SC) probes eliminate the longstanding trade-off between selectivity and durable target capture, achieving selectivity via programmable base pairing and molecular conformation change, and durable target capture via activatable covalent cross-linking. In pure and mixed samples, SC probes covalently capture complementary DNA or RNA oligo targets and reject two-nucleotide mismatched targets with near-quantitative yields at room temperature, achieving discrimination ratios of 2-3 orders of magnitude. Semiquantitative studies with full-length mRNA targets demonstrate selective covalent capture comparable to that for RNA oligo targets. Single-nucleotide DNA or RNA mismatches, including nearly isoenergetic RNA wobble pairs, can be efficiently rejected with discrimination ratios of 1-2 orders of magnitude. Covalent capture yields appear consistent with the thermodynamics of probe/target hybridization, facilitating rational probe design. If desired, cross-links can be reversed to release the target after capture. In contrast to existing probe chemistries, SC probes achieve the high sequence selectivity of a structured probe, yet durably retain their targets even under denaturing conditions. This previously incompatible combination of properties suggests diverse applications based on selective and stable binding of nucleic acid targets under conditions where base-pairing is disrupted (e.g., by stringent washes in vitro or in situ, or by enzymes in vivo).
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Affiliation(s)
- Jeffrey
R. Vieregg
- Department
of Bioengineering, Department of Chemistry, Department of Computing and Mathematical Sciences, California Institute of Technology,
Pasadena, California 91125, United States
| | - Hosea M. Nelson
- Department
of Bioengineering, Department of Chemistry, Department of Computing and Mathematical Sciences, California Institute of Technology,
Pasadena, California 91125, United States
| | - Brian M. Stoltz
- Department
of Bioengineering, Department of Chemistry, Department of Computing and Mathematical Sciences, California Institute of Technology,
Pasadena, California 91125, United States
| | - Niles A. Pierce
- Department
of Bioengineering, Department of Chemistry, Department of Computing and Mathematical Sciences, California Institute of Technology,
Pasadena, California 91125, United States
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Nelson HM, Gordon JR, Virgil SC, Stoltz BM. Total syntheses of (-)-transtaganolide A, (+)-transtaganolide B, (+)-transtaganolide C, and (-)-transtaganolide D and biosynthetic implications. Angew Chem Int Ed Engl 2013; 52:6699-703. [PMID: 23681694 DOI: 10.1002/anie.201301212] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Indexed: 11/08/2022]
Affiliation(s)
- Hosea M Nelson
- Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E. California Boulevard, MC 101-20, Pasadena, CA 91125, USA
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Nelson HM, Gordon JR, Virgil SC, Stoltz BM. Total Syntheses of (−)-Transtaganolide A, (+)-Transtaganolide B, (+)-Transtaganolide C, and (−)-Transtaganolide D and Biosynthetic Implications. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201301212] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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