1
|
Deng Z, Padalino MA, Jan JEL, Park S, Danneman MW, Johnston JN. Generality-Driven Catalyst Development: A Universal Catalyst for Enantioselective Nitroalkene Reduction. J Am Chem Soc 2024; 146:1269-1275. [PMID: 38176098 PMCID: PMC10862354 DOI: 10.1021/jacs.3c12436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2024]
Abstract
Cracking the selectivity-generality paradox is among the most pressing challenges in asymmetric catalysis. This obstacle prevents the immediate and successful translation of new methods to diverse small molecules. This is particularly rate-limiting for therapeutic development, where availability and structural diversity are often critical components of successful campaigns. Here we describe the union of generality-driven enantioselective catalysis and the preparation of diverse peptidomimetics. A single new organocatalyst provides high selectivity and substrate generality that is matched only by a combination of metal and organocatalysts. Within organocatalysis, this discovery breaks a 16-year monolithic paradigm, uncovering a powerful new scaffold for enantioselective reduction with behavior that suggests the recognition of a nitroethylene minimal catalaphile.
Collapse
Affiliation(s)
- Zihang Deng
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235
| | - Melanie A. Padalino
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235
| | - Julius E. L. Jan
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235
| | - Sangjun Park
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235
| | - Michael W. Danneman
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235
| | - Jeffrey N. Johnston
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235
| |
Collapse
|
2
|
Šeflová J, Schwarz JA, Smith AN, Svensson B, Blackwell DJ, Phillips TA, Nikolaienko R, Bovo E, Rebbeck RT, Zima AV, Thomas DD, Van Petegem F, Knollmann BC, Johnston JN, Robia SL, Cornea RL. RyR2 Binding of an Antiarrhythmic Cyclic Depsipeptide Mapped Using Confocal Fluorescence Lifetime Detection of FRET. ACS Chem Biol 2023; 18:2290-2299. [PMID: 37769131 DOI: 10.1021/acschembio.3c00376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/30/2023]
Abstract
Hyperactivity of cardiac sarcoplasmic reticulum (SR) ryanodine receptor (RyR2) Ca2+-release channels contributes to heart failure and arrhythmias. Reducing the RyR2 activity, particularly during cardiac relaxation (diastole), is a desirable therapeutic goal. We previously reported that the unnatural enantiomer (ent) of an insect-RyR activator, verticilide, inhibits porcine and mouse RyR2 at diastolic (nanomolar) Ca2+ and has in vivo efficacy against atrial and ventricular arrhythmia. To determine the ent-verticilide structural mode of action on RyR2 and guide its further development via medicinal chemistry structure-activity relationship studies, here, we used fluorescence lifetime (FLT)-measurements of Förster resonance energy transfer (FRET) in HEK293 cells expressing human RyR2. For these studies, we used an RyR-specific FRET molecular-toolkit and computational methods for trilateration (i.e., using distances to locate a point of interest). Multiexponential analysis of FLT-FRET measurements between four donor-labeled FKBP12.6 variants and acceptor-labeled ent-verticilide yielded distance relationships placing the acceptor probe at two candidate loci within the RyR2 cryo-EM map. One locus is within the Ry12 domain (at the corner periphery of the RyR2 tetrameric complex). The other locus is sandwiched at the interface between helical domain 1 and the SPRY3 domain. These findings document RyR2-target engagement by ent-verticilide, reveal new insight into the mechanism of action of this new class of RyR2-targeting drug candidate, and can serve as input in future computational determinations of the ent-verticilide binding site on RyR2 that will inform structure-activity studies for lead optimization.
Collapse
Affiliation(s)
- Jaroslava Šeflová
- Department of Cell and Molecular Physiology, Loyola University Chicago, Chicago, Illinois 60153, United States
| | - Jacob A Schwarz
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Abigail N Smith
- Department of Chemistry & Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Bengt Svensson
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Daniel J Blackwell
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Taylor A Phillips
- Department of Cell and Molecular Physiology, Loyola University Chicago, Chicago, Illinois 60153, United States
| | - Roman Nikolaienko
- Department of Cell and Molecular Physiology, Loyola University Chicago, Chicago, Illinois 60153, United States
| | - Elisa Bovo
- Department of Cell and Molecular Physiology, Loyola University Chicago, Chicago, Illinois 60153, United States
| | - Robyn T Rebbeck
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Aleksey V Zima
- Department of Cell and Molecular Physiology, Loyola University Chicago, Chicago, Illinois 60153, United States
| | - David D Thomas
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, Life Sciences Centre, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Björn C Knollmann
- Department of Chemistry & Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Jeffrey N Johnston
- Department of Chemistry & Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Seth L Robia
- Department of Cell and Molecular Physiology, Loyola University Chicago, Chicago, Illinois 60153, United States
| | - Răzvan L Cornea
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
| |
Collapse
|
3
|
Zhang G, Cramer N. Reductive Asymmetric Aza-Mislow-Evans Rearrangement by 1,3,2-Diazaphospholene Catalysis. Angew Chem Int Ed Engl 2023; 62:e202301076. [PMID: 36820495 DOI: 10.1002/anie.202301076] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 02/21/2023] [Accepted: 02/23/2023] [Indexed: 02/24/2023]
Abstract
1,3,2-diazaphospholene hydrides (DAP-H) enable smooth conjugate reduction of polarized double bonds. The transiently formed phosphorus-enolate provides a potential platform for reductive α-functionalizations. In this respect, asymmetric C-heteroatom bond forming processes are synthetically appealing but remain elusive. We report a 1,3,2-diazaphospholene-catalyzed three-step cascade reaction of N-sulfinyl acrylamides comprised of conjugate reduction, [2,3]-sigmatropic aza-Mislow-Evans rearrangement and subsequent S-O bond cleavage. The obtained enantio-enriched α-hydroxy amides are formed in good yields and excellent enantiospecificity. The stereo-defined P-bound N,O-ketene aminal ensures an excellent transfer of chirality from the sulfur stereocenter to α-carbon. The transformation operates under mild conditions at ambient temperature. Moreover, DAP-H is a competent reductant for the cleavage of formed sulfenate ester, eliminating the extra step in traditional Mislow-Evans processes.
Collapse
Affiliation(s)
- Guoting Zhang
- Institute of Chemical Sciences and Engineering (ISIC), EPFL SB ISIC LCSA, BCH 4305, 1015, Lausanne, Switzerland
| | - Nicolai Cramer
- Institute of Chemical Sciences and Engineering (ISIC), EPFL SB ISIC LCSA, BCH 4305, 1015, Lausanne, Switzerland
| |
Collapse
|
4
|
Crocker MS, Deng Z, Johnston JN. Preparation of N-Aryl Amides by Epimerization-Free Umpolung Amide Synthesis. J Am Chem Soc 2022; 144:16708-16714. [PMID: 36067492 PMCID: PMC9634722 DOI: 10.1021/jacs.2c05986] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Amide synthesis is one of the most widely practiced chemical reactions, owing to its use in drug development and peptide synthesis. Despite the importance of these applications, the attendant effort to eliminate waste associated with these protocols has met with limited success, and pernicious α-epimerization is most often minimized but not eliminated when targeting challenging amides (e.g., N-aryl amides). This effort has focused on what is essentially a single paradigm in amide formation wherein an electrophilic acyl donor reacts with a nucleophilic amine. Umpolung amide synthesis (UmAS) emerged from α-halo nitroalkane reactions with amines and has since been developed into a method for the synthesis of enantiopure amides using entirely catalytic, enantioselective synthesis. However, its inability to forge N-aryl amides has been a longstanding problem, one limiting its application more broadly in drug development where α-chiral N-aryl amides are increasingly common. We report here the reaction of α-fluoronitroalkanes and N-aryl hydroxyl amines for the direct synthesis of N-aryl amides using a simple Brønsted base as the promoter. No other activating agents are required, and experiments guided by mechanistic hypotheses outline a mechanism based on the UmAS paradigm and confirm that the N-aryl amide, not the N-aryl hydroxamic acid, is the direct product. Ultimately, select chiral α-amino-N-aryl amides were prepared with complete conservation of enantioenrichment, in contrast to a parallel demonstration of their ability to epimerize using the conventional amide synthesis alternative.
Collapse
Affiliation(s)
- Michael S. Crocker
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, USA
| | - Zihang Deng
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, USA
| | - Jeffrey N. Johnston
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, USA
| |
Collapse
|
5
|
Wu QX, Shu T, Fang WY, Qin HL. Discovery of KOH+BrCH2SO2F as a Water‐Removable System for the Clean, Mild and Robust Synthesis of Amides and Peptides. European J Org Chem 2022. [DOI: 10.1002/ejoc.202200719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Qi-Xin Wu
- Wuhan University of Technology School of Chemistry, Chemical Engineering and Life Sciences Wuhan CHINA
| | - Tao Shu
- Wuhan University of Technology School of Chemistry, Chemical Engineering and Life Sciences Wuhan CHINA
| | - Wan-Yin Fang
- Wuhan University of Technology School of Chemistry, Chemical Engineering and Life Sciences Wuhan CHINA
| | - Hua-Li Qin
- Wuhan University of Technology Chemistry 205 Luoshi Road 430070 Wuhan CHINA
| |
Collapse
|
6
|
White AM, Palombi IR, Malins LR. Umpolung strategies for the functionalization of peptides and proteins. Chem Sci 2022; 13:2809-2823. [PMID: 35382479 PMCID: PMC8905898 DOI: 10.1039/d1sc06133j] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 01/04/2022] [Indexed: 01/02/2023] Open
Abstract
Umpolung strategies, defined as synthetic approaches which reverse commonly accepted reactivity patterns, are broadly recognized as enabling tools for small molecule synthesis and catalysis. However, methods which exploit this logic for peptide and protein functionalizations are comparatively rare, with the overwhelming majority of existing bioconjugation approaches relying on the well-established reactivity profiles of a handful of amino acids. This perspective serves to highlight a small but growing body of recent work that masterfully capitalizes on the concept of polarity reversal for the selective modification of proteinogenic functionalities. Current applications of umpolung chemistry in organic synthesis and chemical biology as well as the vast potential for further innovations in peptide and protein modification will be discussed.
Collapse
Affiliation(s)
- Andrew M White
- Research School of Chemistry, Australian National University Canberra ACT 2601 Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Australian National University Canberra ACT 2601 Australia
| | - Isabella R Palombi
- Research School of Chemistry, Australian National University Canberra ACT 2601 Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Australian National University Canberra ACT 2601 Australia
| | - Lara R Malins
- Research School of Chemistry, Australian National University Canberra ACT 2601 Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Australian National University Canberra ACT 2601 Australia
| |
Collapse
|
7
|
Zhang S, Li X, Li W, Rao W, Ge D, Shen Z, Chu X. Iron(0)-Mediated Henry-Type Reaction of Bromonitromethane with Aldehydes for the Efficient Synthesis of 2-Nitro-alkan-1-ols. CHINESE J ORG CHEM 2022. [DOI: 10.6023/cjoc202107048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
8
|
Smith AN, Johnston JN. The Formation of Impossible Rings in Macrocyclooligomerizations for Cyclodepsipeptide Synthesis: The 18-from-12 Paradox. J Org Chem 2021; 86:7904-7919. [PMID: 34097410 DOI: 10.1021/acs.joc.0c03069] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A reinvestigation into the macrocyclooligomerization (MCO) of a tetradepsipeptide is reported, uncovering a paradox in which the MCO of depsipeptide monomers can produce "impossible" ring sizes: a 12-atom chain produced the expected 24-membered ring, alongside unexpected 18- and 30-membered cyclic oligomeric depsipeptides (CODs). We report an alternative preparation of authentic 18- and 36-membered macrocycles for this case using a stepwise synthesis that provides definitive analytical characterization for each ring size. Our investigation yields a recharacterization and reassignment of two macrocycles originally reported in this MCO series, along with updated yields and isothermal titration calorimetry data after implementation of new critical protocols for purification and subsequent analysis. Initial studies to probe this mechanistic conundrum are described.
Collapse
Affiliation(s)
- Abigail N Smith
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Jeffrey N Johnston
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
| |
Collapse
|
9
|
Connon R, Roche B, Rokade BV, Guiry PJ. Further Developments and Applications of Oxazoline-Containing Ligands in Asymmetric Catalysis. Chem Rev 2021; 121:6373-6521. [PMID: 34019404 PMCID: PMC8277118 DOI: 10.1021/acs.chemrev.0c00844] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Indexed: 12/27/2022]
Abstract
The chiral oxazoline motif is present in many ligands that have been extensively applied in a series of important metal-catalyzed enantioselective reactions. This Review aims to provide a comprehensive overview of the most significant applications of oxazoline-containing ligands reported in the literature starting from 2009 until the end of 2018. The ligands are classified not by the reaction to which their metal complexes have been applied but by the nature of the denticity, chirality, and donor atoms involved. As a result, the continued development of ligand architectural design from mono(oxazolines), to bis(oxazolines), to tris(oxazolines) and tetra(oxazolines) and variations thereof can be more easily monitored by the reader. In addition, the key transition states of selected asymmetric transformations will be given to illustrate the features that give rise to high levels of asymmetric induction. As a further aid to the reader, we summarize the majority of schemes with representative examples that highlight the variation in % yields and % ees for carefully selected substrates. This Review should be of particular interest to the experts in the field but also serve as a useful starting point to new researchers in this area. It is hoped that this Review will stimulate both the development/design of new ligands and their applications in novel metal-catalyzed asymmetric transformations.
Collapse
Affiliation(s)
- Robert Connon
- Synthesis
and Solid State Pharmaceutical Centre, Centre for Synthesis and Chemical
Biology, School of Chemistry, University
College Dublin, Dublin
4, Ireland
| | - Brendan Roche
- Synthesis
and Solid State Pharmaceutical Centre, Centre for Synthesis and Chemical
Biology, School of Chemistry, University
College Dublin, Dublin
4, Ireland
| | - Balaji V. Rokade
- BiOrbic
Research Centre, Centre for Synthesis and Chemical Biology, School
of Chemistry, University College Dublin, Dublin 4, Ireland
| | - Patrick J. Guiry
- Synthesis
and Solid State Pharmaceutical Centre, Centre for Synthesis and Chemical
Biology, School of Chemistry, University
College Dublin, Dublin
4, Ireland
- BiOrbic
Research Centre, Centre for Synthesis and Chemical Biology, School
of Chemistry, University College Dublin, Dublin 4, Ireland
| |
Collapse
|
10
|
Sanz-Marco A, Martinez-Erro S, Pauze M, Gómez-Bengoa E, Martín-Matute B. An umpolung strategy to react catalytic enols with nucleophiles. Nat Commun 2019; 10:5244. [PMID: 31748504 PMCID: PMC6868166 DOI: 10.1038/s41467-019-13175-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 10/24/2019] [Indexed: 01/07/2023] Open
Abstract
The selective synthesis of α-functionalized ketones with two similar enolizable positions can be accomplished using allylic alcohols and iridium(III) catalysts. A formal 1,3-hydrogen shift on allylic alcohols generates catalytic iridium-enolates in a stereospecific manner, which are able to react with electrophiles to yield α-functionalized ketones as single constitutional isomers. However, the employment of nucleophiles to react with the nucleophilic catalytic enolates in this chemistry is still unknown. Herein, we report an umpolung strategy for the selective synthesis of α-alkoxy carbonyl compounds by the reaction of iridium enolates and alcohols promoted by an iodine(III) reagent. Moreover, the protocol also works in an intramolecular fashion to synthesize 3(2H)-furanones from γ-keto allylic alcohols. Experimental and computational investigations have been carried out, and mechanisms are proposed for both the inter- and intramolecular reactions, explaining the key role of the iodine(III) reagent in this umpolung approach. Nucleophiles cannot be directly reacted with enolates due to polarity mismatching. Here, the authors developed an umpolung strategy for the selective synthesis of α-alkoxy carbonyl compounds by reaction of iridium enolates with nucleophilic alcohols promoted by an iodine(III) reagent.
Collapse
Affiliation(s)
- Amparo Sanz-Marco
- Department of Organic Chemistry, Stockholm University, Stockholm, SE-10691, Sweden
| | - Samuel Martinez-Erro
- Department of Organic Chemistry, Stockholm University, Stockholm, SE-10691, Sweden
| | - Martin Pauze
- Department of Organic Chemistry, Stockholm University, Stockholm, SE-10691, Sweden.,Departamento de Química Orgánica I, Universidad del País Vasco/UPV-EHU, Manuel de Lardizabal 3, Donostia - San Sebastián, 20018, Spain
| | - Enrique Gómez-Bengoa
- Departamento de Química Orgánica I, Universidad del País Vasco/UPV-EHU, Manuel de Lardizabal 3, Donostia - San Sebastián, 20018, Spain
| | - Belén Martín-Matute
- Department of Organic Chemistry, Stockholm University, Stockholm, SE-10691, Sweden.
| |
Collapse
|
11
|
Zhou M, Li J, Tian C, Sun X, Zhu X, Cheng Y, An G, Li G. A Metal-Free Three-Component Reaction of trans-β-Nitrostyrene Derivatives, Dibromo Amides, and Amines Leading to Functionalized Amidines. J Org Chem 2019; 84:1015-1024. [PMID: 30592406 DOI: 10.1021/acs.joc.8b02998] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A mild, metal-free, and multicomponent route for the preparation of N-acyl amidines from nitroalkene derivatives, dibromo amides, and amines has been developed that accesses an initial α,α-dibromonitroalkane intermediate that can undergo C-C bond cleavage. This protocol offers an alternative approach toward N-acyl amidines and features the rapid construction of amidine frameworks with high diversity and complexity. The procedure also accesses bisamidine and α,β-unsaturated amidines which are challenging targets by traditional methods.
Collapse
Affiliation(s)
- Meng Zhou
- Key Laboratory of Functional Inorganic Material Chemistry (MOE), School of Chemistry and Materials Science , Heilongjiang University , No. 74, Xuefu Road , Nangang District, Harbin 150080 , People's Republic of China
| | - Jinlei Li
- Key Laboratory of Functional Inorganic Material Chemistry (MOE), School of Chemistry and Materials Science , Heilongjiang University , No. 74, Xuefu Road , Nangang District, Harbin 150080 , People's Republic of China
| | - Chao Tian
- Key Laboratory of Functional Inorganic Material Chemistry (MOE), School of Chemistry and Materials Science , Heilongjiang University , No. 74, Xuefu Road , Nangang District, Harbin 150080 , People's Republic of China
| | - Xiao Sun
- Key Laboratory of Functional Inorganic Material Chemistry (MOE), School of Chemistry and Materials Science , Heilongjiang University , No. 74, Xuefu Road , Nangang District, Harbin 150080 , People's Republic of China
| | - Xiaoting Zhu
- Key Laboratory of Functional Inorganic Material Chemistry (MOE), School of Chemistry and Materials Science , Heilongjiang University , No. 74, Xuefu Road , Nangang District, Harbin 150080 , People's Republic of China
| | - Yaohang Cheng
- Key Laboratory of Functional Inorganic Material Chemistry (MOE), School of Chemistry and Materials Science , Heilongjiang University , No. 74, Xuefu Road , Nangang District, Harbin 150080 , People's Republic of China
| | - Guanghui An
- Key Laboratory of Functional Inorganic Material Chemistry (MOE), School of Chemistry and Materials Science , Heilongjiang University , No. 74, Xuefu Road , Nangang District, Harbin 150080 , People's Republic of China.,College of Materials Science and Chemical Engineering , Harbin Engineering University , Harbin , Heilongjiang 150001 , People's Republic of China
| | - Guangming Li
- Key Laboratory of Functional Inorganic Material Chemistry (MOE), School of Chemistry and Materials Science , Heilongjiang University , No. 74, Xuefu Road , Nangang District, Harbin 150080 , People's Republic of China
| |
Collapse
|
12
|
Li Y, Zhou K, Wen Z, Cao S, Shen X, Lei M, Gong L. Copper(II)-Catalyzed Asymmetric Photoredox Reactions: Enantioselective Alkylation of Imines Driven by Visible Light. J Am Chem Soc 2018; 140:15850-15858. [DOI: 10.1021/jacs.8b09251] [Citation(s) in RCA: 131] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Yanjun Li
- Key Laboratory of Chemical Biology of Fujian Province, iChEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China
| | - Kexu Zhou
- Key Laboratory of Chemical Biology of Fujian Province, iChEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China
| | - Zhaorui Wen
- Key Laboratory of Chemical Biology of Fujian Province, iChEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China
| | - Shi Cao
- Key Laboratory of Chemical Biology of Fujian Province, iChEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China
| | - Xiang Shen
- Key Laboratory of Chemical Biology of Fujian Province, iChEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China
| | - Meng Lei
- Key Laboratory of Chemical Biology of Fujian Province, iChEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China
| | - Lei Gong
- Key Laboratory of Chemical Biology of Fujian Province, iChEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China
| |
Collapse
|
13
|
Batiste SM, Johnston JN. Evidence for Ion-Templation During Macrocyclooligomerization of Depsipeptides. J Am Chem Soc 2018; 140:4560-4568. [PMID: 29565576 PMCID: PMC5996984 DOI: 10.1021/jacs.7b13148] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The ion-mediated Mitsunobu macrocyclooligomerization (M-MCO) reaction of hydroxy acid depsipeptides provides small collections of cyclic depsipeptides with good mass recovery. The approach can produce good yields of a single macrocycle or provide rapid access to multiple oligomeric macrocycles in good overall yield. While Lewis acidic alkali metal salts are known to play a role in the outcome of MCO reactions, it is unclear whether their effect is due to an organizational (e.g., templating) mechanism. Isothermal titration calorimetry (ITC) was used to study macrocycle-metal ion binding interactions, and this report correlates these thermodynamic measurements to the (kinetically determined) size distributions of depsipeptides formed during a Mitsunobu-based macrocyclooligomerization (MCO). Key trends have been identified in quantitative metal ion-cyclic depsipeptide binding affinity ( Ka), enthalpy of binding (Δ H), and stoichiometry of complexation across discrete series of macrocycles, and they provide the first analytical platform to rationally select a metal-ion template for a targeted size regime of cyclic oligomeric depsipeptides.
Collapse
Affiliation(s)
- Suzanne M Batiste
- Department of Chemistry and Vanderbilt Institute of Chemical Biology , Vanderbilt University , Nashville , Tennessee 37235-1822 , United States
| | - Jeffrey N Johnston
- Department of Chemistry and Vanderbilt Institute of Chemical Biology , Vanderbilt University , Nashville , Tennessee 37235-1822 , United States
| |
Collapse
|
14
|
Ghosh S, Jana CK. Metal-Free Thermal Activation of Molecular Oxygen Enabled Direct α-CH 2-Oxygenation of Free Amines. J Org Chem 2017; 83:260-266. [PMID: 29182340 DOI: 10.1021/acs.joc.7b02630] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Direct oxidation of α-CH2 group of free amines is hard to achieve due to the higher reactivity of amine moiety. Therefore, oxidation of amines involves the use of sophisticated metallic reagents/catalyst in the presence or absence of hazardous oxidants under sensitive reaction conditions. A novel method for direct C-H oxygenation of aliphatic amines through a metal-free activation of molecular oxygen has been developed. Both activated and unactivated free amines were oxygenated efficiently to provide a wide variety of amides (primary, secondary) and lactams under operationally simple conditions without the aid of metallic reagents and toxic oxidants. The method has been applied to the synthesis of highly functionalized amide-containing medicinal drugs, such as O-Me-alibendol and -buclosamide.
Collapse
Affiliation(s)
- Santanu Ghosh
- Department of Chemistry, Indian Institute of Technology Guwahati , Guwahati, India 781039
| | - Chandan K Jana
- Department of Chemistry, Indian Institute of Technology Guwahati , Guwahati, India 781039
| |
Collapse
|
15
|
Otevrel J, Bobal P. Diamine-Tethered Bis(thiourea) Organocatalyst for Asymmetric Henry Reaction. J Org Chem 2017; 82:8342-8358. [DOI: 10.1021/acs.joc.7b00079] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Jan Otevrel
- Department of Chemical Drugs,
Faculty of Pharmacy, University of Veterinary and Pharmaceutical Sciences (UVPS) Brno, Palackeho 1946/1, 612 42 Brno, Czech Republic
| | - Pavel Bobal
- Department of Chemical Drugs,
Faculty of Pharmacy, University of Veterinary and Pharmaceutical Sciences (UVPS) Brno, Palackeho 1946/1, 612 42 Brno, Czech Republic
| |
Collapse
|
16
|
Zhao Z, Peng Z, Zhao Y, Liu H, Li C, Zhao J. Hypervalent Iodine-Mediated Oxidative Rearrangement of N–H Ketimines: An Umpolung Approach to Amides. J Org Chem 2017; 82:11848-11853. [DOI: 10.1021/acs.joc.7b01468] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Zhenguang Zhao
- Key Laboratory of Chemical
Biology of Jiangxi Province, College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang, Jiangxi 330022, People’s Republic of China
| | - Zhiyuan Peng
- Key Laboratory of Chemical
Biology of Jiangxi Province, College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang, Jiangxi 330022, People’s Republic of China
| | - Yongli Zhao
- Key Laboratory of Chemical
Biology of Jiangxi Province, College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang, Jiangxi 330022, People’s Republic of China
| | - Hao Liu
- Key Laboratory of Chemical
Biology of Jiangxi Province, College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang, Jiangxi 330022, People’s Republic of China
| | - Chongnan Li
- Key Laboratory of Chemical
Biology of Jiangxi Province, College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang, Jiangxi 330022, People’s Republic of China
| | - Junfeng Zhao
- Key Laboratory of Chemical
Biology of Jiangxi Province, College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang, Jiangxi 330022, People’s Republic of China
| |
Collapse
|
17
|
Yang J, Zhao J. Recent developments in peptide ligation independent of amino acid side-chain functional group. Sci China Chem 2017. [DOI: 10.1007/s11426-017-9056-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
18
|
Park SY, Hwang IS, Lee HJ, Song CE. Biomimetic catalytic transformation of toxic α-oxoaldehydes to high-value chiral α-hydroxythioesters using artificial glyoxalase I. Nat Commun 2017; 8:14877. [PMID: 28374736 PMCID: PMC5382281 DOI: 10.1038/ncomms14877] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 02/07/2017] [Indexed: 12/22/2022] Open
Abstract
Glyoxalase I plays a critical role in the enzymatic defence against glycation by catalysing the isomerization of hemithioacetal, formed spontaneously from cytotoxic α-oxoaldehydes and glutathione, to (S)-α-hydroxyacylglutathione derivatives. Upon the hydrolysis of the thioesters catalysed by glyoxalase II, inert (S)-α-hydroxy acids, that is, lactic acid, are then produced. Herein, we demonstrate highly enantioselective glyoxalase I mimic catalytic isomerization of in-situ-generated hemithioacetals, providing facile access to both enantiomers of α-hydroxy thioesters. Owing to the flexibility of thioesters, a family of optically pure α-hydroxyamides, which are highly important drug candidates in the pharmaceutical industry, were prepared without any coupling reagents. Similar to real enzymes, the enforced proximity of the catalyst and substrates by the chiral cage in situ formed by the incorporation of potassium salt can enhance the reactivity and efficiently transfer the stereochemical information.
Collapse
Affiliation(s)
- Sang Yeon Park
- Department of Chemistry, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi 440-746, Korea
| | - In-Soo Hwang
- Department of Chemistry, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi 440-746, Korea
| | - Hyun-Ju Lee
- Department of Chemistry, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi 440-746, Korea
| | - Choong Eui Song
- Department of Chemistry, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi 440-746, Korea
| |
Collapse
|
19
|
Tokumaru K, Johnston JN. A convergent synthesis of 1,3,4-oxadiazoles from acyl hydrazides under semiaqueous conditions. Chem Sci 2017; 8:3187-3191. [PMID: 28507694 PMCID: PMC5414388 DOI: 10.1039/c7sc00195a] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 02/16/2017] [Indexed: 12/22/2022] Open
Abstract
The 1,3,4-oxadiazole is an aromatic heterocycle valued for its low-lipophilicity in drug development. Substituents at the 2- and/or 5-positions can modulate the heterocycle's electronic and hydrogen bond-accepting capability, while exploiting its use as a carbonyl bioisostere. A new approach to 1,3,4-oxadiazoles is described wherein α-bromo nitroalkanes are coupled to acyl hydrazides to deliver the 2,5-disubstituted oxadiazole directly, avoiding a 1,2-diacyl hydrazide intermediate. Access to new building blocks of oxadiazole-substituted secondary amines is improved by leveraging chiral α-bromo nitroalkane or amino acid hydrazide substrates. The non-dehydrative conditions for oxadiazole synthesis are particularly notable, in contrast to alternatives reliant on highly oxophilic reagents to effect cyclization of unsymmetrical 1,2-diacyl hydrazides. The mild conditions are punctuated by the straightforward removal of co-products by a standard aqueous wash.
Collapse
Affiliation(s)
- Kazuyuki Tokumaru
- Department of Chemistry , Vanderbilt Institute of Chemical Biology , Vanderbilt University , Nashville , Tennessee 37235 , USA .
| | - Jeffrey N Johnston
- Department of Chemistry , Vanderbilt Institute of Chemical Biology , Vanderbilt University , Nashville , Tennessee 37235 , USA .
| |
Collapse
|
20
|
Zhu J, Gao B, Huang H. Palladium-catalyzed highly regioselective hydroaminocarbonylation of aromatic alkenes to branched amides. Org Biomol Chem 2017; 15:2910-2913. [DOI: 10.1039/c7ob00371d] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Pd(t-Bu3P)2 has been successfully identified as an efficient catalyst for the hydroaminocarbonylation of aromatic alkenes to branched amides under relatively mild reaction conditions.
Collapse
Affiliation(s)
- Jinping Zhu
- College of Chemical Engineering
- Zhejiang University of Technology
- Hangzhou
- China
| | - Bao Gao
- Department of Chemistry
- University of Science and Technology of China
- Hefei
- China
| | - Hanmin Huang
- College of Chemical Engineering
- Zhejiang University of Technology
- Hangzhou
- China
- Department of Chemistry
| |
Collapse
|
21
|
Rapid synthesis of cyclic oligomeric depsipeptides with positional, stereochemical, and macrocycle size distribution control. Proc Natl Acad Sci U S A 2016; 113:14893-14897. [PMID: 27974608 DOI: 10.1073/pnas.1616462114] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Macrocyclic small molecules are attractive tools in the development of sensors, new materials, and therapeutics. Within early-stage drug discovery, they are increasingly sought for their potential to interact with broad surfaces of peptidic receptors rather than within their narrow folds and pockets. Cyclization of linear small molecule precursors is a straightforward strategy to constrain conformationally mobile motifs, but forging a macrocycle bond typically becomes more difficult at larger ring sizes. We report the development of a general approach to discrete collections of oligomeric macrocyclic depsipeptides using an oligomerization/macrocyclization process governed by a series of Mitsunobu reactions of hydroxy acid monomers. Ring sizes of 18, 24, 30, and 36 are formed in a single reaction from a didepsipeptide, whereas sizes of 24, 36, and 60 result from a tetradepsipeptide. The ring-size selectivity inherent to the approach can be modulated by salt additives that enhance the formation of specific ring sizes. Use of chemical synthesis to prepare the monomers suggests broad access to functionally and stereochemically diverse collections of natural product-like oligodepsipeptide macrocycles. Two cyclodepsipeptide natural products were prepared along with numerous unnatural oligomeric congeners to provide rapid access to discrete collections of complex macrocyclic small molecules from medium (18) to large (60) ring sizes.
Collapse
|
22
|
Ghosh S, Jana CK. Aminofluorene-Mediated Biomimetic Domino Amination–Oxygenation of Aldehydes to Amides. Org Lett 2016; 18:5788-5791. [DOI: 10.1021/acs.orglett.6b02465] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Santanu Ghosh
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039, India
| | - Chandan K. Jana
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039, India
| |
Collapse
|
23
|
Vara BA, Johnston JN. Enantioselective Synthesis of β-Fluoro Amines via β-Amino α-Fluoro Nitroalkanes and a Traceless Activating Group Strategy. J Am Chem Soc 2016; 138:13794-13797. [PMID: 27749040 PMCID: PMC5453840 DOI: 10.1021/jacs.6b07731] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Preparation of a range of enantioenriched β-fluoro amines (α,β-disubstituted) is described in which the nitrogen and fluorine atoms are attached to sp3-hybridized carbons. The key finding is a chiral bifunctional Brønsted acid/base catalyst that can deliver β-amino-α-fluoro nitroalkanes with high enantio- and diastereoselection. A denitration step renders the nitro group "traceless" and delivers secondary, tertiary, or vinyl alkyl fluorides embedded within a vicinal fluoro amine functional group. A synthesis of each possible stereoisomer of a β-fluoro lanicemine illustrates the potential ease with which fluorinated small molecules relevant to neuroscience drug development can be prepared in a stereochemically comprehensive manner.
Collapse
Affiliation(s)
- Brandon A. Vara
- Department of Chemistry & Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37235-1822
| | - Jeffrey N. Johnston
- Department of Chemistry & Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37235-1822
| |
Collapse
|
24
|
Abstract
The present review offers an overview of nonclassical (e.g., with no pre- or in situ activation of a carboxylic acid partner) approaches for the construction of amide bonds. The review aims to comprehensively discuss relevant work, which was mainly done in the field in the last 20 years. Organization of the data follows a subdivision according to substrate classes: catalytic direct formation of amides from carboxylic and amines ( section 2 ); the use of carboxylic acid surrogates ( section 3 ); and the use of amine surrogates ( section 4 ). The ligation strategies (NCL, Staudinger, KAHA, KATs, etc.) that could involve both carboxylic acid and amine surrogates are treated separately in section 5 .
Collapse
Affiliation(s)
- Renata Marcia de Figueiredo
- Institut Charles Gerhardt de Montpellier (ICGM), UMR 5253-CNRS-UM-ENSCM, Ecole Nationale Supérieure de Chimie , 8 rue de l'Ecole Normale, 34296 Montpellier Cedex 5, France
| | - Jean-Simon Suppo
- Institut Charles Gerhardt de Montpellier (ICGM), UMR 5253-CNRS-UM-ENSCM, Ecole Nationale Supérieure de Chimie , 8 rue de l'Ecole Normale, 34296 Montpellier Cedex 5, France
| | - Jean-Marc Campagne
- Institut Charles Gerhardt de Montpellier (ICGM), UMR 5253-CNRS-UM-ENSCM, Ecole Nationale Supérieure de Chimie , 8 rue de l'Ecole Normale, 34296 Montpellier Cedex 5, France
| |
Collapse
|
25
|
Hu Y, Shen Z, Huang H. Palladium-Catalyzed Intramolecular Hydroaminocarbonylation to Lactams: Additive-Free Protocol Initiated by Palladium Hydride. ACS Catal 2016. [DOI: 10.1021/acscatal.6b01939] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Yue Hu
- State
Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou
Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000, People’s Republic of China
- University of Chinese
Academy of Sciences, Beijing, 100049, People’s Republic of China
| | - Zhiqiang Shen
- State
Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou
Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000, People’s Republic of China
| | - Hanmin Huang
- State
Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou
Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000, People’s Republic of China
- Department
of Chemistry, University of Science and Technology of China, Hefei, 230026, People’s Republic of China
| |
Collapse
|
26
|
Saikia I, Borah AJ, Phukan P. Use of Bromine and Bromo-Organic Compounds in Organic Synthesis. Chem Rev 2016; 116:6837-7042. [PMID: 27199233 DOI: 10.1021/acs.chemrev.5b00400] [Citation(s) in RCA: 281] [Impact Index Per Article: 35.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Bromination is one of the most important transformations in organic synthesis and can be carried out using bromine and many other bromo compounds. Use of molecular bromine in organic synthesis is well-known. However, due to the hazardous nature of bromine, enormous growth has been witnessed in the past several decades for the development of solid bromine carriers. This review outlines the use of bromine and different bromo-organic compounds in organic synthesis. The applications of bromine, a total of 107 bromo-organic compounds, 11 other brominating agents, and a few natural bromine sources were incorporated. The scope of these reagents for various organic transformations such as bromination, cohalogenation, oxidation, cyclization, ring-opening reactions, substitution, rearrangement, hydrolysis, catalysis, etc. has been described briefly to highlight important aspects of the bromo-organic compounds in organic synthesis.
Collapse
Affiliation(s)
| | - Arun Jyoti Borah
- Department of Chemistry, Gauahti University , Guwahati-781014, Assam, India
| | - Prodeep Phukan
- Department of Chemistry, Gauahti University , Guwahati-781014, Assam, India
| |
Collapse
|
27
|
Kaldun J, Prause F, Scharnagel D, Freitag F, Breuning M. Evaluation of 5-cis-Substituted Prolinamines as Ligands in Enantioselective, Copper-Catalyzed Henry Reactions. ChemCatChem 2016. [DOI: 10.1002/cctc.201600240] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Johannes Kaldun
- Organic Chemistry Laboratory; University of Bayreuth; Universitätsstraße 30 95447 Bayreuth Germany
| | - Felix Prause
- Organic Chemistry Laboratory; University of Bayreuth; Universitätsstraße 30 95447 Bayreuth Germany
| | - Dagmar Scharnagel
- Organic Chemistry Laboratory; University of Bayreuth; Universitätsstraße 30 95447 Bayreuth Germany
| | - Frederik Freitag
- Organic Chemistry Laboratory; University of Bayreuth; Universitätsstraße 30 95447 Bayreuth Germany
| | - Matthias Breuning
- Organic Chemistry Laboratory; University of Bayreuth; Universitätsstraße 30 95447 Bayreuth Germany
| |
Collapse
|
28
|
Li J, Lear MJ, Kwon E, Hayashi Y. Mechanism of Oxidative Amidation of Nitroalkanes with Oxygen and Amine Nucleophiles by Using Electrophilic Iodine. Chemistry 2016; 22:5538-42. [DOI: 10.1002/chem.201600540] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Indexed: 11/11/2022]
Affiliation(s)
- Jing Li
- Department of Chemistry; Graduate School of Science; Tohoku University; Aza Aramaki, Aoba-ku Sendai 980-8578 Japan
| | - Martin J. Lear
- School of Chemistry; University of Lincoln; Brayford Pool Lincoln LN6 7TS UK
| | - Eunsang Kwon
- Research and Analytical Center for Giant Molecules, Graduate School of Science; Tohoku University; Sendai 980-8578 Japan
| | - Yujiro Hayashi
- Department of Chemistry; Graduate School of Science; Tohoku University; Aza Aramaki, Aoba-ku Sendai 980-8578 Japan
| |
Collapse
|
29
|
Murai K, Matsuura K, Aoyama H, Fujioka H. Oxidative Rearrangement via in Situ Generated N-Chloroamine: Synthesis of Fused Tetrahydroisoquinolines. Org Lett 2016; 18:1314-7. [PMID: 26926911 DOI: 10.1021/acs.orglett.6b00233] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An oxidative rearrangement reaction of spiro tetrahydroisoquinolines has been developed for the synthesis of fused tetrahydroisoquinolines using in situ generated N-chloroamines. The reaction proceeds via initial chlorination of an amine, followed by a 1,2-carbon to nitrogen migration, and nucleophilic trapping of a ketiminium ion intermediate in a one-pot operation. The electrophilic nature of N-chloroamines allowed for the carbon-nitrogen bond formation in this reation.
Collapse
Affiliation(s)
- Kenichi Murai
- Graduate School of Pharmaceutical Sciences, Osaka University , 1-6 Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Kei Matsuura
- Graduate School of Pharmaceutical Sciences, Osaka University , 1-6 Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Hiroshi Aoyama
- Graduate School of Pharmaceutical Sciences, Osaka University , 1-6 Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Hiromichi Fujioka
- Graduate School of Pharmaceutical Sciences, Osaka University , 1-6 Yamada-oka, Suita, Osaka 565-0871, Japan
| |
Collapse
|
30
|
Zhang G, Ji X, Yu H, Yang L, Jiao P, Huang H. Palladium-catalyzed hydroaminocarbonylation of alkenes with amines promoted by weak acid. Tetrahedron Lett 2016. [DOI: 10.1016/j.tetlet.2015.12.031] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
|
31
|
Abstract
A two-step, one-pot oxidative amidation of primary nitroalkanes involving tandem halogenation/umpolung amide synthesis (UmAS) is described.
Collapse
Affiliation(s)
- Kenneth E. Schwieter
- Department of Chemistry and Vanderbilt Institute of Chemical Biology
- Vanderbilt University
- Nashville
- USA
| | - Jeffrey N. Johnston
- Department of Chemistry and Vanderbilt Institute of Chemical Biology
- Vanderbilt University
- Nashville
- USA
| |
Collapse
|
32
|
Li J, Lear MJ, Kawamoto Y, Umemiya S, Wong AR, Kwon E, Sato I, Hayashi Y. Oxidative Amidation of Nitroalkanes with Amine Nucleophiles using Molecular Oxygen and Iodine. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201505192] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
|
33
|
Li J, Lear MJ, Kawamoto Y, Umemiya S, Wong AR, Kwon E, Sato I, Hayashi Y. Oxidative Amidation of Nitroalkanes with Amine Nucleophiles using Molecular Oxygen and Iodine. Angew Chem Int Ed Engl 2015; 54:12986-90. [DOI: 10.1002/anie.201505192] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2015] [Revised: 07/18/2015] [Indexed: 02/03/2023]
Affiliation(s)
- Jing Li
- Department of Chemistry, Graduate School of Science, Tohoku University, 6‐3 Aramaki‐Aza, Aoba‐ku, Sendai 980‐8578 (Japan) http://www.ykbsc.chem.tohoku.ac.jp
| | - Martin J. Lear
- Department of Chemistry, Graduate School of Science, Tohoku University, 6‐3 Aramaki‐Aza, Aoba‐ku, Sendai 980‐8578 (Japan) http://www.ykbsc.chem.tohoku.ac.jp
- Present address: School of Chemistry, University of Lincoln, Brayford Pool, Lincoln LN6 7TS (UK)
| | - Yuya Kawamoto
- Department of Chemistry, Graduate School of Science, Tohoku University, 6‐3 Aramaki‐Aza, Aoba‐ku, Sendai 980‐8578 (Japan) http://www.ykbsc.chem.tohoku.ac.jp
| | - Shigenobu Umemiya
- Department of Chemistry, Graduate School of Science, Tohoku University, 6‐3 Aramaki‐Aza, Aoba‐ku, Sendai 980‐8578 (Japan) http://www.ykbsc.chem.tohoku.ac.jp
| | - Alice R. Wong
- Department of Chemistry, Graduate School of Science, Tohoku University, 6‐3 Aramaki‐Aza, Aoba‐ku, Sendai 980‐8578 (Japan) http://www.ykbsc.chem.tohoku.ac.jp
| | - Eunsang Kwon
- Research and Analytical Center for Giant Molecules, Graduate School of Science, Tohoku University, Sendai 980‐8578 (Japan)
| | - Itaru Sato
- Department of Chemistry, Graduate School of Science, Tohoku University, 6‐3 Aramaki‐Aza, Aoba‐ku, Sendai 980‐8578 (Japan) http://www.ykbsc.chem.tohoku.ac.jp
- Present address: Faculty of Science, Ibaraki University, Ibaraki 310‐8512 (Japan)
| | - Yujiro Hayashi
- Department of Chemistry, Graduate School of Science, Tohoku University, 6‐3 Aramaki‐Aza, Aoba‐ku, Sendai 980‐8578 (Japan) http://www.ykbsc.chem.tohoku.ac.jp
| |
Collapse
|
34
|
Ballini R, Petrini M. The Nitro to Carbonyl Conversion (Nef Reaction): New Perspectives for a Classical Transformation. Adv Synth Catal 2015. [DOI: 10.1002/adsc.201500008] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
|
35
|
Zhang G, Gao B, Huang H. Palladium-catalyzed hydroaminocarbonylation of alkenes with amines: a strategy to overcome the basicity barrier imparted by aliphatic amines. Angew Chem Int Ed Engl 2015; 54:7657-61. [PMID: 25959632 DOI: 10.1002/anie.201502405] [Citation(s) in RCA: 114] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Revised: 04/20/2015] [Indexed: 12/14/2022]
Abstract
A novel and efficient palladium-catalyzed hydroaminocarbonylation of alkenes with aminals has been developed under mild reaction conditions, and allows the synthesis of a wide range of N-alkyl linear amides in good yields with high regioselectivity. On the basis of this method, a cooperative catalytic system operating by the synergistic combination of palladium, paraformaldehyde, and acid was established for promoting the hydroaminocarbonylation of alkenes with both aromatic and aliphatic amines, which do not react well under conventional palladium-catalyzed hydroaminocarbonylation.
Collapse
Affiliation(s)
- Guoying Zhang
- State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China)
| | - Bao Gao
- State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China)
| | - Hanmin Huang
- State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China).
| |
Collapse
|
36
|
Zhang G, Gao B, Huang H. Palladium-Catalyzed Hydroaminocarbonylation of Alkenes with Amines: A Strategy to Overcome the Basicity Barrier Imparted by Aliphatic Amines. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201502405] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
|
37
|
Schwieter KE, Johnston JN. Enantioselective Synthesis of D-α-Amino Amides from Aliphatic Aldehydes. Chem Sci 2015; 6:2590-2595. [PMID: 25838883 PMCID: PMC4378585 DOI: 10.1039/c5sc00064e] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Bromonitromethane is used in a phase transfer-catalysed enantioselective aza-Henry reaction, leading to d-amino amide bearing an alkyl chain.
Peptides consisting of d-amino amides are highly represented among both biologically active natural products and non-natural small molecules used in therapeutic development. Chemical synthesis of d-amino amides most often involves approaches based on enzymatic resolution or fractional recrystallization of their diastereomeric amino acid salt precursors, techniques that produce an equal amount of the l-amino acid. Enantioselective synthesis, however, promises selective and general access to a specific α-amino amide, and may enable efficient peptide synthesis regardless of the availability of the corresponding α-amino acid. This report describes the use of a cinchona alkaloid-catalyzed aza-Henry reaction using bromonitromethane, and the integration of its product with umpolung amide synthesis. The result is a straightforward 3-step protocol beginning from aliphatic aldehydes that provides homologated peptides bearing an aliphatic side chain at the resulting d-α-amino amide.
Collapse
Affiliation(s)
- Kenneth E Schwieter
- Department of Chemistry and Vanderbilt Institute of Chemical Biology Vanderbilt University, Nashville, Tennessee 37235
| | - Jeffrey N Johnston
- Department of Chemistry and Vanderbilt Institute of Chemical Biology Vanderbilt University, Nashville, Tennessee 37235
| |
Collapse
|
38
|
Schwieter KE, Johnston JN. Enantioselective Addition of Bromonitromethane to Aliphatic N-Boc Aldimines Using a Homogeneous Bifunctional Chiral Organocatalyst. ACS Catal 2015; 5:6559-6562. [PMID: 27019764 DOI: 10.1021/acscatal.5b01901] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
This report details the enantioselective synthesis of β-amino-α-bromo nitroalkanes with β-alkyl substituents, using homogeneous catalysis to prepare either antipode. Use of a bifunctional Brønsted base/acid catalyst allows equal access to either enantiomer of the products, enabling the use of Umpolung Amide Synthesis (UmAS) to prepare the corresponding L- or D-α-amino amide bearing alkyl side chains - overall, in only 4 steps from aldehyde. The approach also addresses an underlying incompatibility between bromonitromethane and solid hydroxide bases.
Collapse
Affiliation(s)
- Kenneth E. Schwieter
- Department of Chemistry and
Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Jeffrey N. Johnston
- Department of Chemistry and
Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
| |
Collapse
|
39
|
Massolo E, Benaglia M, Genoni A, Annunziata R, Celentano G, Gaggero N. Stereoselective reaction of 2-carboxythioesters-1,3-dithiane with nitroalkenes: an organocatalytic strategy for the asymmetric addition of a glyoxylate anion equivalent. Org Biomol Chem 2015; 13:5591-6. [DOI: 10.1039/c5ob00492f] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Under mild reaction conditions γ-nitro-β-aryl-α-keto esters with up to 92% ee were obtained, realizing a formal catalytic stereoselective conjugate addition of the glyoxylate anion synthon.
Collapse
Affiliation(s)
- Elisabetta Massolo
- Dipartimento di Chimica
- Universita’ degli Studi di Milano
- I-20133 Milano
- Italy
| | - Maurizio Benaglia
- Dipartimento di Chimica
- Universita’ degli Studi di Milano
- I-20133 Milano
- Italy
| | - Andrea Genoni
- Dipartimento di Chimica
- Universita’ degli Studi di Milano
- I-20133 Milano
- Italy
| | - Rita Annunziata
- Dipartimento di Chimica
- Universita’ degli Studi di Milano
- I-20133 Milano
- Italy
| | - Giuseppe Celentano
- Dipartimento di Scienze Farmaceutiche
- Università degli Studi di Milano
- Milano
- Italy
| | - Nicoletta Gaggero
- Dipartimento di Scienze Farmaceutiche
- Università degli Studi di Milano
- Milano
- Italy
| |
Collapse
|
40
|
Yang KS, Rawal VH. Synthesis of α-amino acid derivatives and peptides via enantioselective addition of masked acyl cyanides to imines. J Am Chem Soc 2014; 136:16148-51. [PMID: 25366558 PMCID: PMC4244832 DOI: 10.1021/ja510135t] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
![]()
A general,
asymmetric synthesis of amino acid derivatives is reported. Masked
acyl cyanide (MAC) reagents are shown to be effective umpolung synthons
for enantioselective additions to N-Boc-aldimines.
The reactions are catalyzed by a modified cinchona alkaloid, which
can function as a bifunctional, hydrogen bonding catalyst, and afford
adducts in excellent yields (90–98%) and high enantioselectivities
(up to 97.5:2.5 er). Unmasking the addition products gives acyl cyanide
intermediates that are intercepted by a variety of nucleophiles to
afford α-amino acid derivatives. Notably, the methodology provides
an alternative method for peptide bond formation.
Collapse
Affiliation(s)
- Kin S Yang
- Department of Chemistry, The University of Chicago , Chicago, Illinois 60637, United States
| | | |
Collapse
|
41
|
Schwieter KE, Shen B, Shackleford JP, Leighty MW, Johnston JN. Umpolung amide synthesis using substoichiometric N-iodosuccinimide (NIS) and oxygen as a terminal oxidant. Org Lett 2014; 16:4714-7. [PMID: 25198239 PMCID: PMC4168777 DOI: 10.1021/ol502089v] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
![]()
Umpolung Amide Synthesis
(UmAS) provides direct access to amides
from an α-bromo nitroalkane and an amine. Based on its mechanistic
bifurcation after convergent C–N bond formation, depending
on the absence or presence of oxygen, UmAS using substoichiometric N-iodosuccinimide (NIS) under aerobic conditions
has been developed. In combination with the enantioselective preparation
of α-bromo nitroalkane donors, this protocol realizes the goal
of enantioselective α-amino amide and peptide synthesis based
solely on catalytic methods.
Collapse
Affiliation(s)
- Kenneth E Schwieter
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University , Nashville, Tennessee 37235, United States
| | | | | | | | | |
Collapse
|
42
|
Soengas RG, Acúrcio RC, Silva AMS. Recent Developments in the Chemistry ofgem-Halonitro Compounds. European J Org Chem 2014. [DOI: 10.1002/ejoc.201402043] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
43
|
Ma B, Miao T, Sun Y, He Y, Liu J, Feng Y, Chen H, Fan QH. A New Class of Tunable Dendritic Diphosphine Ligands: Synthesis and Applications in the Ru-Catalyzed Asymmetric Hydrogenation of Functionalized Ketones. Chemistry 2014; 20:9969-78. [DOI: 10.1002/chem.201402709] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Indexed: 11/07/2022]
|
44
|
Makley DM, Johnston JN. Silyl imine electrophiles in enantioselective catalysis: a Rosetta Stone for peptide homologation, enabling diverse N-protected aryl glycines from aldehydes in three steps. Org Lett 2014; 16:3146-9. [PMID: 24828455 PMCID: PMC4059254 DOI: 10.1021/ol501297a] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
![]()
We report that N-(trimethylsilyl)imines serve
in the Bis(AMidine)-catalyzed addition of bromonitromethane with a
high degree of enantioselection. This allows for the production of
a range of protected α-bromo nitroalkane donors (including Fmoc)
for use in Umpolung Amide Synthesis (UmAS). Hence, peptide homologation
with nonnatural aryl glycine amino acids is achieved in three steps
from aromatic aldehydes, which are plentiful and inexpensive. Epimerization
during the homologation step is circumvented by avoiding an α-amino
acid intermediate.
Collapse
Affiliation(s)
- Dawn M Makley
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University , Nashville, Tennessee 37235, United States
| | | |
Collapse
|
45
|
Scharnagel D, Prause F, Kaldun J, Haase RG, Breuning M. (2S,5R)-2-Methylaminomethyl-1-methyl-5-phenylpyrrolidine, a chiral diamine ligand for copper(ii)-catalysed Henry reactions with superb enantiocontrol. Chem Commun (Camb) 2014; 50:6623-5. [DOI: 10.1039/c4cc02429j] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Copper(ii)-complexes of a cis-2-aminomethyl-5-phenylpyrrolidine catalyse enantioselective Henry reactions with extraordinarily high stereocontrol.
Collapse
Affiliation(s)
- Dagmar Scharnagel
- Organic Chemistry Laboratory
- University of Bayreuth
- 95447 Bayreuth, Germany
| | - Felix Prause
- Organic Chemistry Laboratory
- University of Bayreuth
- 95447 Bayreuth, Germany
| | - Johannes Kaldun
- Organic Chemistry Laboratory
- University of Bayreuth
- 95447 Bayreuth, Germany
| | - Robert G. Haase
- Organic Chemistry Laboratory
- University of Bayreuth
- 95447 Bayreuth, Germany
| | - Matthias Breuning
- Organic Chemistry Laboratory
- University of Bayreuth
- 95447 Bayreuth, Germany
| |
Collapse
|
46
|
Drouet F, Zhu J, Masson G. Iron Chloride‐Catalyzed Three‐Component Domino Sequences: Syntheses of Functionalized α‐Oxy‐N‐acylhemiaminals and α‐Oxyimides. Adv Synth Catal 2013. [DOI: 10.1002/adsc.201300847] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Fleur Drouet
- Centre de Recherche de Gif, Institut de Chimie des Substances Naturelles, CNRS, 91198 Gif‐sur‐Yvette Cedex, France, homepage: http://www.icsn.cnrs‐gif.fr/spip.php?article225
| | - Jieping Zhu
- Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), EPFL‐SB‐ISIC LSPN, CH‐1015 Lausanne, Switzerland
| | - Géraldine Masson
- Centre de Recherche de Gif, Institut de Chimie des Substances Naturelles, CNRS, 91198 Gif‐sur‐Yvette Cedex, France, homepage: http://www.icsn.cnrs‐gif.fr/spip.php?article225
| |
Collapse
|
47
|
Yang KS, Nibbs AE, Türkmen YE, Rawal VH. Squaramide-catalyzed enantioselective Michael addition of masked acyl cyanides to substituted enones. J Am Chem Soc 2013; 135:16050-3. [PMID: 24090310 PMCID: PMC3968543 DOI: 10.1021/ja409012q] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Indexed: 01/20/2023]
Abstract
Masked acyl cyanide (MAC) reagents are shown to be effective umpolung synthons for enantioselective Michael addition to substituted enones. The reactions are catalyzed by chiral squaramides and afford adducts in high yields (90-99%) and with excellent enantioselectivities (85-98%). The addition products are unmasked to produce dicyanohydrins that, upon treatment with a variety of nucleophiles, provide γ-keto acids, esters, and amides. The use of this umpolung synthon has enabled, in enantiomerically enriched form, the first total synthesis of the prenylated phenol (+)-fornicin C.
Collapse
Affiliation(s)
- Kin S. Yang
- Department of Chemistry, The
University of Chicago, Chicago, Illinois 60637, United States
| | - Antoinette E. Nibbs
- Department of Chemistry, The
University of Chicago, Chicago, Illinois 60637, United States
| | - Yunus E. Türkmen
- Department of Chemistry, The
University of Chicago, Chicago, Illinois 60637, United States
| | - Viresh H. Rawal
- Department of Chemistry, The
University of Chicago, Chicago, Illinois 60637, United States
| |
Collapse
|
48
|
Zhou Y, Zhu Y, Yan S, Gong Y. Copper-Catalyzed Enantioselective Henry Reaction of Enals and Subsequent Iodocyclization: Stereoselective Construction of Chiral Azatricyclic Frameworks. Angew Chem Int Ed Engl 2013; 52:10265-9. [DOI: 10.1002/anie.201305148] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2013] [Indexed: 11/08/2022]
|
49
|
Zhou Y, Zhu Y, Yan S, Gong Y. Copper-Catalyzed Enantioselective Henry Reaction of Enals and Subsequent Iodocyclization: Stereoselective Construction of Chiral Azatricyclic Frameworks. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201305148] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
|
50
|
Organocatalytic aldol reaction of indole-3-carbaldehydes with ketones: synthesis of chiral 3-substituted indoles. Tetrahedron Lett 2013. [DOI: 10.1016/j.tetlet.2013.06.056] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|