1
|
Cassels WR, Sherman ER, Longmore KA, Johnson JS. Switchable Enantio- and Diastereoselective Michael Additions of β-Keto Amides to Nitroolefins: Crystallization-Based Inversion of Kinetic Stereocontrol. Org Lett 2024; 26:7176-7180. [PMID: 39151143 DOI: 10.1021/acs.orglett.4c02617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/18/2024]
Abstract
Asymmetric catalytic reactions rely on chiral catalysts that induce highly ordered transition states capable of imparting stereoselectivity in the bond-forming step(s). Productive deviations from this paradigm are rare yet hold the potential for accessing different stereoisomers using the same catalyst. Here, we present an enantio- and diastereoselective Michael addition of β-keto amides to nitroolefin electrophiles proceeding via an unusual scenario where the kinetic diastereocontrol imparted by the catalyst may be overridden by crystallization to provide the complementary stereoisomer of the product.
Collapse
Affiliation(s)
- William R Cassels
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Emily R Sherman
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Kaylah A Longmore
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Jeffrey S Johnson
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| |
Collapse
|
2
|
Ma C, Lindsley CW, Chang J, Yu B. Rational Molecular Editing: A New Paradigm in Drug Discovery. J Med Chem 2024; 67:11459-11466. [PMID: 38905482 DOI: 10.1021/acs.jmedchem.4c01347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/23/2024]
Affiliation(s)
- Chunhua Ma
- State Key Laboratory of Antiviral Drugs, Pingyuan Laboratory, NMPA Key Laboratory for Research and Evaluation of Innovative Drug, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
| | - Craig W Lindsley
- Vanderbilt University Medical Center, Franklin, Tennessee 37027, United States
| | - Junbiao Chang
- College of Chemistry, Pingyuan Laboratory, State Key Laboratory of Antiviral Drugs, Zhengzhou University, Zhengzhou 450001, China
| | - Bin Yu
- College of Chemistry, Pingyuan Laboratory, State Key Laboratory of Antiviral Drugs, Zhengzhou University, Zhengzhou 450001, China
| |
Collapse
|
3
|
Müller DS, Charki P, Cordier M, Gellrich U. Utilization of 13C NMR Carbon Shifts for the Attribution of Diastereomers in Methyl-Substituted Cyclohexanes. J Org Chem 2024; 89:8668-8675. [PMID: 38856090 DOI: 10.1021/acs.joc.4c00602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
In this report, we address the challenge of assigning diastereomers for methyl cyclohexanes, particularly those with quaternary centers, which remains nontrivial despite modern NMR techniques. By utilizing a HSQC NMR experiment to identify methyl-carbons coupled with a simple conformational analysis, we identified an effective and quite general method for assigning stereochemistry, even in cases where diastereomeric mixtures are inseparable.
Collapse
Affiliation(s)
- Daniel S Müller
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes)-UMR 6226, F-35000 Rennes, France
| | - Paul Charki
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes)-UMR 6226, F-35000 Rennes, France
| | - Marie Cordier
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes)-UMR 6226, F-35000 Rennes, France
| | - Urs Gellrich
- Department of Organic Chemistry, University of Hohenheim, Garbenstrasse 30, 70599 Stuttgart, Germany
| |
Collapse
|
4
|
Grant PS, Vavrík M, Porte V, Meyrelles R, Maulide N. Remote proton elimination: C-H activation enabled by distal acidification. Science 2024; 384:815-820. [PMID: 38753789 DOI: 10.1126/science.adi8997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 04/08/2024] [Indexed: 05/18/2024]
Abstract
Generally, the acidity of carbon-hydrogen bonds is most sensitive to functionality just one or two bonds away. Here, we present an approach to the formation of carbon-carbon σ bonds by remote proton elimination, a distinct mode of carbon-hydrogen activation enabled by distal acidification through five carbon-carbon bonds. Application of remote proton elimination to cyclodecyl cations unveiled an appealing method for the synthesis of decalins. The transformation is regioconvergent, proceeds without the need for a directing group or precious metal, and demonstrates exquisite site selectivity. An in-depth computational study illuminated the reaction mechanism. Additionally, we describe the complete stereoisomeric enrichment of the decalin products through epimerization mediated by hydrogen atom transfer.
Collapse
Affiliation(s)
- Phillip S Grant
- Institute of Organic Chemistry, University of Vienna, 1090 Vienna, Austria
| | - Miloš Vavrík
- Institute of Organic Chemistry, University of Vienna, 1090 Vienna, Austria
| | - Vincent Porte
- Institute of Organic Chemistry, University of Vienna, 1090 Vienna, Austria
| | - Ricardo Meyrelles
- Institute of Organic Chemistry, University of Vienna, 1090 Vienna, Austria
- Institute of Theoretical Chemistry, University of Vienna, 1090 Vienna, Austria
| | - Nuno Maulide
- Institute of Organic Chemistry, University of Vienna, 1090 Vienna, Austria
| |
Collapse
|
5
|
Hong BC, Indurmuddam RR. Tetrabutylammonium decatungstate (TBADT), a compelling and trailblazing catalyst for visible-light-induced organic photocatalysis. Org Biomol Chem 2024; 22:3799-3842. [PMID: 38651982 DOI: 10.1039/d4ob00171k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
Tetrabutylammonium decatungstate (TBADT) has recently emerged as an intriguing photocatalyst under visible-light or near-visible-light irradiation in a wide range of organic reactions that were previously not conceivable. Given its ability to absorb visible light and excellent effectiveness in activating unactivated chemical bonds, it is a promising addition to traditional photocatalysts. This review covers some of the contemporary developments in visible-light or near-visible-light photocatalysis reactions enabled by the TBADT catalyst to 2023, with the contents organized by reaction type.
Collapse
Affiliation(s)
- Bor-Cherng Hong
- Department of Chemistry and Biochemistry, National Chung Cheng University, Chiayi 621, Taiwan.
| | | |
Collapse
|
6
|
Rehpenn A, Hindelang S, Truong KN, Pöthig A, Storch G. Enhancing Flavins Photochemical Activity in Hydrogen Atom Abstraction and Triplet Sensitization through Ring-Contraction. Angew Chem Int Ed Engl 2024; 63:e202318590. [PMID: 38339882 DOI: 10.1002/anie.202318590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 01/30/2024] [Accepted: 02/01/2024] [Indexed: 02/12/2024]
Abstract
The isoalloxazine heterocycle of flavin cofactors reacts with various nucleophiles to form covalent adducts with important functions in enzymes. Molecular flavin models allow for the characterization of such adducts and the study of their properties. A fascinating set of reactions occurs when flavins react with hydroxide base, which leads to imidazolonequinoxalines, ring-contracted flavins, with so far unexplored activity. We report a systematic study of the photophysical properties of this new chromophore by absorption and emission spectroscopy as well as cyclic voltammetry. Excited, ring-contracted flavins are significantly stronger hydrogen atom abstractors when compared to the parent flavins, which allowed the direct trifluoromethylthiolation of aliphatic methine positions (bond dissociation energy (BDE) of 400.8 kJ mol-1). In an orthogonal activity, their increased triplet energy (E(S0←T1)=244 kJ mol-1) made sensitized reactions possible which exceeded the power of standard flavins. Combining both properties, ring-contracted flavin catalysts enabled the one-pot, five-step transformation of α-tropolone into trans-3,4-disubstituted cyclopentanones. We envision this new class of flavin-derived chromophores to open up new modes of reactivity that are currently impossible with unmodified flavins.
Collapse
Affiliation(s)
- Andreas Rehpenn
- Technical University of Munich (TUM), School of Natural Sciences and Catalysis Research Center (CRC), Lichtenbergstr. 4, 85747, Garching, Germany
| | - Stephan Hindelang
- Technical University of Munich (TUM), School of Natural Sciences and Catalysis Research Center (CRC), Lichtenbergstr. 4, 85747, Garching, Germany
| | - Khai-Nghi Truong
- Rigaku Europe SE, Hugenottenallee 167, 63263, Neu-Isenburg, Germany
| | - Alexander Pöthig
- Technical University of Munich (TUM), School of Natural Sciences and Catalysis Research Center (CRC), Lichtenbergstr. 4, 85747, Garching, Germany
| | - Golo Storch
- Technical University of Munich (TUM), School of Natural Sciences and Catalysis Research Center (CRC), Lichtenbergstr. 4, 85747, Garching, Germany
| |
Collapse
|
7
|
Singh PP, Sinha S, Gahtori P, Tivari S, Srivastava V. Recent advances of decatungstate photocatalyst in HAT process. Org Biomol Chem 2024; 22:2523-2538. [PMID: 38456306 DOI: 10.1039/d4ob00213j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2024]
Abstract
The decatungstate anion (W10O324-) appears to exhibit especially interesting properties as a photocatalyst. Because of its unique photocatalytic properties, it is now recognised as a promising tool in organic chemistry. This study examines recent advances in decatungstate chemistry, primarily concerned with synthetic and, to some degree, mechanistic challenges. In this short review we have selected to give a number of illustrative examples that demonstrate the various applications of decatungstate in the hydrogen atom transfer (HAT) process.
Collapse
Affiliation(s)
- Praveen P Singh
- Department of Chemistry, United College of Engineering & Research, Prayagraj, U.P.-211010, India.
| | - Surabhi Sinha
- Department of Chemistry, United College of Engineering & Research, Prayagraj, U.P.-211010, India.
| | - Prashant Gahtori
- School of Pharmacy, Graphic Era Hill University, Dehradun, 248002 Uttarakhand, India
| | - Shraddha Tivari
- Department of Chemistry, CMP Degree College, University of Allahabad, Prayagraj, U.P.-211002, India.
| | - Vishal Srivastava
- Department of Chemistry, CMP Degree College, University of Allahabad, Prayagraj, U.P.-211002, India.
| |
Collapse
|
8
|
Vargas-Rivera MA, Liu AS, Ellman JA. Visible-Light-Mediated, Diastereoselective Epimerization of Exocyclic Amines. Org Lett 2023; 25:9197-9201. [PMID: 38114418 PMCID: PMC10771010 DOI: 10.1021/acs.orglett.3c03801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2023]
Abstract
Stereoselective α-amino C-H epimerization of exocyclic amines is achieved via photoredox catalyzed, thiyl-radical mediated, reversible hydrogen atom transfer to provide thermodynamically controlled anti/syn isomer ratios. The method is applicable to different substituents and substitution patterns about aminocyclopentanes, aminocyclohexanes, and a N-Boc-3-aminopiperidine. The method also provided efficient epimerization for primary, alkyl and (hetero)aryl secondary, and tertiary exocyclic amines. Demonstration of reversible epimerization, deuterium labeling, and luminescence quenching provides insight into the reaction mechanism.
Collapse
Affiliation(s)
| | - Aidan S. Liu
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Jonathan A. Ellman
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| |
Collapse
|
9
|
Yuan Z, Britton R. Development and application of decatungstate catalyzed C-H 18F- and 19F-fluorination, fluoroalkylation and beyond. Chem Sci 2023; 14:12883-12897. [PMID: 38023504 PMCID: PMC10664588 DOI: 10.1039/d3sc04027e] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 10/11/2023] [Indexed: 12/01/2023] Open
Abstract
Over the past few decades, photocatalytic C-H functionalization reactions have received increasing attention due to the often mild reaction conditions and complementary selectivities to conventional functionalization processes. Now, photocatalytic C-H functionalization is a widely employed tool, supporting activities ranging from complex molecule synthesis to late-stage structure-activity relationship studies. In this perspective, we will discuss our efforts in developing a photocatalytic decatungstate catalyzed C-H fluorination reaction as well as its practical application realized through collaborations with industry partners at Hoffmann-La Roche and Merck, and extension to radiofluorination with radiopharmaceutical chemists and imaging experts at TRIUMF and the BC Cancer Agency. Importantly, we feel that our efforts address a question of utility posed by Professor Tobias Ritter in "Late-Stage Fluorination: Fancy Novelty or Useful Tool?" (ACIE, 2015, 54, 3216). In addition, we will discuss decatungstate catalyzed C-H fluoroalkylation and the interesting electrostatic effects observed in decatungstate-catalyzed C-H functionalization. We hope this perspective will inspire other researchers to explore the use of decatungstate for the purposes of photocatalytic C-H functionalization and further advance the exploitation of electrostatic effects for both rate acceleration and directing effects in these reactions.
Collapse
Affiliation(s)
- Zheliang Yuan
- Department of Chemistry, Simon Fraser University Burnaby British Columbia V5A 1S2 Canada
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Department of Chemistry, Zhejiang Normal University Jinhua Zhejiang 321004 China
| | - Robert Britton
- Department of Chemistry, Simon Fraser University Burnaby British Columbia V5A 1S2 Canada
| |
Collapse
|
10
|
Großkopf J, Plaza M, Kutta RJ, Nuernberger P, Bach T. Creating a Defined Chirality in Amino Acids and Cyclic Dipeptides by Photochemical Deracemization. Angew Chem Int Ed Engl 2023; 62:e202313606. [PMID: 37793026 DOI: 10.1002/anie.202313606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 09/30/2023] [Accepted: 10/02/2023] [Indexed: 10/06/2023]
Abstract
2,5-Diketopiperazines are cyclic dipeptides displaying a wide range of applications. Their enantioselective preparation has now been found possible from the respective racemates by a photochemical deracemization (53 examples, 74 % to quantitative yield, 71-99 % ee). A chiral benzophenone catalyst in concert with irradiation at λ=366 nm enables to establish the configuration at the stereogenic carbon atom C6 at will. If other stereogenic centers are present in the diketopiperazines they remain unaffected and a stereochemical editing is possible at a single position. Consecutive reactions, including the conversion into N-aryl or N-alkyl amino acids or the reduction to piperazines, occur without compromising the newly created stereogenic center. Transient absorption spectroscopy revealed that the benzophenone catalyst processes one enantiomer of the 2,5-diketopiperazines preferentially and enables a reversible hydrogen atom transfer that is responsible for the deracemization process. The remarkably long lifetime of the protonated ketyl radical implies a yet unprecedented mode of action.
Collapse
Affiliation(s)
- Johannes Großkopf
- Department Chemie and Catalysis Research Center (CRC), School of Natural Sciences, Technische Universität München, D-85747, Garching, Germany
| | - Manuel Plaza
- Department Chemie and Catalysis Research Center (CRC), School of Natural Sciences, Technische Universität München, D-85747, Garching, Germany
| | - Roger Jan Kutta
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, Universitätsstr. 31, D-93053, Regensburg, Germany
| | - Patrick Nuernberger
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, Universitätsstr. 31, D-93053, Regensburg, Germany
| | - Thorsten Bach
- Department Chemie and Catalysis Research Center (CRC), School of Natural Sciences, Technische Universität München, D-85747, Garching, Germany
| |
Collapse
|
11
|
Brägger Y, Green O, Bhawal BN, Morandi B. Late-Stage Molecular Editing Enabled by Ketone Chain-Walking Isomerization. J Am Chem Soc 2023; 145:19496-19502. [PMID: 37640367 PMCID: PMC10510328 DOI: 10.1021/jacs.3c05680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Indexed: 08/31/2023]
Abstract
Herein, a method for the isomerization of ketones in a manner akin to the chain-walking reaction of alkenes is described. Widely available and inexpensive pyrrolidine and elemental sulfur are deployed as catalysts to achieve this reversible transformation. Key to the utility of this approach was the elucidation of a stereochemical model to determine the thermodynamically favored product of the reaction and the kinetic selectivity observed. With the distinct selectivity profile of our ketone chain-walking process, the isomerization of various steroids was demonstrated to rapidly access novel steroids with "unnatural" oxidation patterns.
Collapse
Affiliation(s)
- Yannick Brägger
- ETH
Zürich, Vladimir-Prelog-Weg 3, HCI, 8093 Zürich, Switzerland
| | - Ori Green
- ETH
Zürich, Vladimir-Prelog-Weg 3, HCI, 8093 Zürich, Switzerland
| | - Benjamin N. Bhawal
- ETH
Zürich, Vladimir-Prelog-Weg 3, HCI, 8093 Zürich, Switzerland
- School
of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, U.K.
| | - Bill Morandi
- ETH
Zürich, Vladimir-Prelog-Weg 3, HCI, 8093 Zürich, Switzerland
| |
Collapse
|
12
|
Chen K, Zeng Q, Xie L, Xue Z, Wang J, Xu Y. Functional-group translocation of cyano groups by reversible C-H sampling. Nature 2023; 620:1007-1012. [PMID: 37364765 DOI: 10.1038/s41586-023-06347-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 06/20/2023] [Indexed: 06/28/2023]
Abstract
Chemical transformations that introduce, remove or manipulate functional groups are ubiquitous in synthetic chemistry1. Unlike conventional functional-group interconversion reactions that swap one functionality for another, transformations that alter solely the location of functional groups are far less explored. Here, by photocatalytic, reversible C-H sampling, we report a functional-group translocation reaction of cyano (CN) groups in common nitriles, allowing for the direct positional exchange between a CN group and an unactivated C-H bond. The reaction shows high fidelity for 1,4-CN translocation, frequently contrary to inherent site selectivity in conventional C-H functionalizations. We also report the direct transannular CN translocation of cyclic systems, providing access to valuable structures that are non-trivial to obtain by other methods. Making use of the synthetic versatility of CN and a key CN translocation step, we showcase concise syntheses of building blocks of bioactive molecules. Furthermore, the combination of C-H cyanation and CN translocation allows access to unconventional C-H derivatives. Overall, the reported reaction represents a way to achieve site-selective C-H transformation reactions without requiring a site-selective C-H cleavage step.
Collapse
Affiliation(s)
- Ken Chen
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Qingrui Zeng
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Longhuan Xie
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Zisheng Xue
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Jianbo Wang
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Yan Xu
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, China.
| |
Collapse
|
13
|
Hejna BG, Ganley JM, Shao H, Tian H, Ellefsen JD, Fastuca NJ, Houk KN, Miller SJ, Knowles RR. Catalytic Asymmetric Hydrogen Atom Transfer: Enantioselective Hydroamination of Alkenes. J Am Chem Soc 2023; 145:16118-16129. [PMID: 37432783 PMCID: PMC10544660 DOI: 10.1021/jacs.3c04591] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/13/2023]
Abstract
We report a highly enantioselective radical-based hydroamination of enol esters with sulfonamides jointly catalyzed by an Ir photocatalyst, Brønsted base, and tetrapeptide thiol. This method is demonstrated for the formation of 23 protected β-amino-alcohol products, achieving selectivities up to 97:3 er. The stereochemistry of the product is set through selective hydrogen atom transfer from the chiral thiol catalyst to a prochiral C-centered radical. Structure-selectivity relationships derived from structural variation of both the peptide catalyst and olefin substrate provide key insights into the development of an optimal catalyst. Experimental and computational mechanistic studies indicate that hydrogen-bonding, π-π stacking, and London dispersion interactions are contributing factors for substrate recognition and enantioinduction. These findings further the development of radical-based asymmetric catalysis and contribute to the understanding of the noncovalent interactions relevant to such transformations.
Collapse
Affiliation(s)
- Benjamin G. Hejna
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Jacob M. Ganley
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Huiling Shao
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Haowen Tian
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Jonathan D. Ellefsen
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Nicholas J. Fastuca
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - K. N. Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Scott J. Miller
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Robert R. Knowles
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| |
Collapse
|
14
|
Streety X, Obike JC, Townsend SD. A Hitchhiker's Guide to Problem Selection in Carbohydrate Synthesis. ACS CENTRAL SCIENCE 2023; 9:1285-1296. [PMID: 37521800 PMCID: PMC10375882 DOI: 10.1021/acscentsci.3c00507] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Indexed: 08/01/2023]
Abstract
Oligosaccharides are ubiquitous in molecular biology and are used for functions ranging from governing protein folding to intercellular communication. Perhaps paradoxically, the exact role of the glycan in most of these settings is not well understood. One reason for this contradiction concerns the fact that carbohydrates often appear in heterogeneous form in nature. These mixtures complicate the isolation of pure material and characterization of structure-activity relationships. As a result, a major bottleneck in glycoscience research is the synthesis and modification of pure materials. While synthetic and chemoenzymatic methods have enabled access to homogeneous tool compounds, a central problem, particularly for newer synthetic chemists, is the matter of problem selection. This outlook aims to provide an entry level overview of fundamental principles in carbohydrate chemistry with an eye toward enabling solutions to frontier challenges.
Collapse
|
15
|
Castellino NJ, Montgomery AP, Danon JJ, Kassiou M. Late-stage Functionalization for Improving Drug-like Molecular Properties. Chem Rev 2023. [PMID: 37285604 DOI: 10.1021/acs.chemrev.2c00797] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The development of late-stage functionalization (LSF) methodologies, particularly C-H functionalization, has revolutionized the field of organic synthesis. Over the past decade, medicinal chemists have begun to implement LSF strategies into their drug discovery programs, allowing for the drug discovery process to become more efficient. Most reported applications of late-stage C-H functionalization of drugs and drug-like molecules have been to rapidly diversify screening libraries to explore structure-activity relationships. However, there has been a growing trend toward the use of LSF methodologies as an efficient tool for improving drug-like molecular properties of promising drug candidates. In this review, we have comprehensively reviewed recent progress in this emerging area. Particular emphasis is placed on case studies where multiple LSF techniques were implemented to generate a library of novel analogues with improved drug-like properties. We have critically analyzed the current scope of LSF strategies to improve drug-like properties and commented on how we believe LSF can transform drug discovery in the future. Overall, we aim to provide a comprehensive survey of LSF techniques as tools for efficiently improving drug-like molecular properties, anticipating its continued uptake in drug discovery programs.
Collapse
Affiliation(s)
| | | | - Jonathan J Danon
- School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia
| | - Michael Kassiou
- School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia
| |
Collapse
|
16
|
Sanchez A, Gurajapu A, Guo W, Kong WY, Laconsay CJ, Settineri NS, Tantillo DJ, Maimone TJ. A Shapeshifting Roadmap for Polycyclic Skeletal Evolution. J Am Chem Soc 2023. [PMID: 37279177 DOI: 10.1021/jacs.3c03960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Polycyclic ring systems are ubiquitous three-dimensional (3D) structural motifs central to the function of many biologically active small molecules and organic materials. Indeed, subtle changes to the overall molecular shape and connectivity of atoms in a polycyclic framework (i.e., isomerism) can drastically alter its function and properties. Unfortunately, direct evaluation of these structure-function relationships typically requires the development of distinct synthetic strategies toward a specific isomer. Dynamic, "shapeshifting" carbon cages present a promising approach for sampling isomeric chemical space but are often difficult to control and are largely limited to thermodynamic mixtures of positional isomers about a single core scaffold. Here, we describe the development of a new shapeshifting C9-chemotype and a chemical blueprint for its evolution into structurally and energetically diverse isomeric ring systems. By leveraging the unique molecular topology of π-orbitals interacting through-space (homoconjugation), a common skeletal ancestor evolved into a complex network of valence isomers. This unusual system represents an exceedingly rare small molecule capable of undergoing controllable and continuous isomerization processes through the iterative use of just two chemical steps (light and organic base). Computational and photophysical studies of the isomer network provide fundamental insight into the reactivity, mechanism, and role of homoconjugative interactions. Importantly, these insights may inform the rational design and synthesis of new dynamic, shapeshifting systems. We anticipate this process could be a powerful tool for the synthesis of structurally diverse, isomeric polycycles central to many bioactive small molecules and functional organic materials.
Collapse
Affiliation(s)
- Andre Sanchez
- Department of Chemistry, University of California-Berkeley, 826 Latimer Hall, Berkeley, California 94720, United States
| | - Anjali Gurajapu
- Department of Chemistry, University of California-Berkeley, 826 Latimer Hall, Berkeley, California 94720, United States
| | - Wentao Guo
- Department of Chemistry, University of California-Davis, 1 Shields Ave, Davis, California 95616, United States
| | - Wang-Yeuk Kong
- Department of Chemistry, University of California-Davis, 1 Shields Ave, Davis, California 95616, United States
| | - Croix J Laconsay
- Department of Chemistry, University of California-Davis, 1 Shields Ave, Davis, California 95616, United States
| | - Nicholas S Settineri
- Department of Chemistry, University of California-Berkeley, 826 Latimer Hall, Berkeley, California 94720, United States
| | - Dean J Tantillo
- Department of Chemistry, University of California-Davis, 1 Shields Ave, Davis, California 95616, United States
| | - Thomas J Maimone
- Department of Chemistry, University of California-Berkeley, 826 Latimer Hall, Berkeley, California 94720, United States
| |
Collapse
|
17
|
Qiu G, Ni CL, Knowles RR. Isotopic Fractionation as a Mechanistic Probe in Light-Driven C-H Bond Exchange Reactions. J Am Chem Soc 2023; 145:11537-11543. [PMID: 37192535 PMCID: PMC10510749 DOI: 10.1021/jacs.2c11212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Here, we report a diagnostic framework for elucidating the mechanisms of photoredox-based hydrogen isotope exchange (HIE) reactions based on hydrogen/deuterium (H/D) fractionation. Traditional thermal HIE methods generally proceed by reversible bond cleavage and bond reformation steps that share a common transition state. However, bond cleavage and bond reformation in light-driven HIE reactions can proceed via multiple, non-degenerate sets of elementary steps, complicating both mechanistic analysis and attendant optimization efforts. Building on classical treatments of equilibrium isotope effects, the fractionation method presented here extracts information regarding the nature of the key bond-forming and bond-breaking steps by comparing the extent of deuterium incorporation into an exchangeable C-H bond in the substrate relative to the H/D isotopic ratio of a solvent reservoir. We show that the extent of fractionation is sensitive to the mechanism of the exchange process and provides a means to distinguish between degenerate and non-degenerate mechanisms for isotopic exchange. In model systems, the mechanisms implied by the fractionation method align with those predicted by thermochemical considerations. We then employed the method to study HIE reactions whose mechanisms are ambiguous on thermodynamic grounds.
Collapse
Affiliation(s)
| | | | - Robert R. Knowles
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| |
Collapse
|
18
|
Cassels WR, Crawford ET, Johnson JS. Enantio- and Diastereoselective Mannich Reactions of ß-Dicarbonyls by Second Stage Diastereoconvergent Crystallization. ACS Catal 2023; 13:6518-6524. [PMID: 38046476 PMCID: PMC10688612 DOI: 10.1021/acscatal.3c01515] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
The synthesis of chiral α-monosubstituted-ß-dicarbonyls is a challenging task in asymmetric catalysis due to the rapid, typically uncontrolled, product racemization or epimerization under most reaction conditions. For this reason, diastereoselective additions of unsubstituted ß-dicarbonyls to π-electrophiles are unusual. Herein, we disclose a simple catalytic crystallization-driven enantio- and diastereoselective Mannich reaction for the synthesis of stereodefined α-monosubstituted-ß-keto esters, dissymmetric ß-diesters, dissymmetric ß-diketones, and ß-keto amides that productively leverages product epimerization in solution. Mechanistic studies suggest a scenario where the initial enantioselective, diastereodivergent skeletal assembly is catalyzed by a chiral tertiary amine organocatalyst, which then facilitates second stage crystallization-induced diastereoconvergence to provide the challenging α-stereocenter in excellent stereoselectivity.
Collapse
Affiliation(s)
- William R Cassels
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Evan T Crawford
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Jeffrey S Johnson
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| |
Collapse
|
19
|
Montgomery AP, Joyce JM, Danon JJ, Kassiou M. An update on late-stage functionalization in today's drug discovery. Expert Opin Drug Discov 2023; 18:597-613. [PMID: 37114995 DOI: 10.1080/17460441.2023.2205635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
INTRODUCTION Late-stage functionalization (LSF) allows for the introduction of new chemical groups toward the end of a synthetic sequence, which means new molecules can be rapidly accessed without laborious de novo chemical synthesis. Over the last decade, medicinal chemists have begun to implement LSF strategies into their drug discovery programs, affording benefits such as efficient access to diverse libraries to explore structure-activity relationships and the improvement of physicochemical and pharmacokinetic properties. AREAS COVERED An overview of the key advancements in LSF methodology development from 2019 to 2022 and their applicability to drug discovery is provided. In addition, several examples from both academia and industry where LSF methodologies have been applied by medicinal chemists to their drug discovery programs are presented. EXPERT OPINION Utilization of LSF by medicinal chemists is on the rise, both in academia and in industry. The maturation of the LSF field to produce methodologies bearing increased regioselectivity, scope, and functional group tolerance is envisaged to narrow the gap between methodology development and medicinal chemistry research. The authors predict that the sheer versatility of these techniques in facilitating challenging chemical transformations of bioactive molecules will continue to increase the efficiency of the drug discovery process.
Collapse
Affiliation(s)
| | - Jack M Joyce
- School of Chemistry, The University of Sydney, Sydney, Australia
| | - Jonathan J Danon
- School of Chemistry, The University of Sydney, Sydney, Australia
| | - Michael Kassiou
- School of Chemistry, The University of Sydney, Sydney, Australia
| |
Collapse
|
20
|
Tan G, Glorius F. Stereochemical Editing. Angew Chem Int Ed Engl 2023; 62:e202217840. [PMID: 36576752 DOI: 10.1002/anie.202217840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 12/22/2022] [Accepted: 12/28/2022] [Indexed: 12/29/2022]
Abstract
Stereochemical editing has recently risen to prominence, allowing the direct editing of organic molecules with stereocenter(s) to adjust their relative stereochemistry at a late-stage. Several seminal light-driven stereochemical editing reactions such as deracemization and epimerization have been successively developed. Recently, Wendlandt and co-workers reported a versatile photochemical epimerization of unactivated tertiary stereogenic centers to rapidly prepare the stereoisomers that were previously challenging to access.
Collapse
Affiliation(s)
- Guangying Tan
- Westfälische Wilhelms-Universität Münster, Organisch-Chemisches Institut, Corrensstraße 36, 48149, Münster, Germany
| | - Frank Glorius
- Westfälische Wilhelms-Universität Münster, Organisch-Chemisches Institut, Corrensstraße 36, 48149, Münster, Germany
| |
Collapse
|