Journal ArticleDOI
Lewis acid-Lewis acid heterobimetallic cooperative catalysis: mechanistic studies and application in enantioselective aza-Michael reaction.
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TLDR
The full details of a catalytic asymmetric aza-Michael reaction of methoxylamine promoted by rare earth-alkali metal heterobimetallic complexes are described, demonstrating the effectiveness of Lewis acid-Lewis acid cooperative catalysis.Abstract:
The full details of a catalytic asymmetric aza-Michael reaction of methoxylamine promoted by rare earth−alkali metal heterobimetallic complexes are described, demonstrating the effectiveness of Lewis acid−Lewis acid cooperative catalysis. First, enones were used as substrates, and the 1,4-adducts were obtained in good yield (57−98%) and high ee (81−96%). Catalyst loading was successfully reduced to 0.3−3 mol % with enones. To broaden the substrate scope of the reaction to carboxylic acid derivatives, α,β-unsaturated N-acylpyrroles were used as monodentate, carboxylic acid derivatives. With β-alkyl-substituted N-acylpyrroles, the reaction proceeded smoothly and the products were obtained in high yield and good ee. Transformation of the 1,4-adducts from enones and α,β-unsaturated N-acylpyrroles afforded corresponding chiral aziridines and β-amino acids. Detailed mechanistic studies, including kinetics, NMR analysis, nonlinear effects, and rare earth metal effects, are also described. The Lewis acid−Lewis ac...read more
Citations
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Nonlinear Effects in Asymmetric Catalysis
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Cooperative catalysis by silica-supported organic functional groups
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Recent advances in the catalytic asymmetric synthesis of β-amino acids
TL;DR: The progress in catalytic asymmetric synthesis of beta-amino acids is discussed, covering the literature since 2002 and the most important synthetic methods, such as hydrogenation, the Mannich reaction and conjugate additions are covered.
Journal ArticleDOI
Cooperative bimetallic catalysis in asymmetric transformations
Jongwoo Park,Sukwon Hong +1 more
TL;DR: This tutorial review highlights strategies and recent advances in cooperative bimetallic catalysts which have been developed for a variety of asymmetric transformations.
Journal ArticleDOI
An Enantioselective Claisen Rearrangement Catalyzed by N-Heterocyclic Carbenes
TL;DR: Investigations demonstrate that the counterion of the azolium salt plays a key role in the formation of the catalytically active species in the synthesis of enantioenriched kojic acid derivatives.
References
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Journal ArticleDOI
Horner-wadsworth-emmons reaction: Use of lithium chloride and an amine for base-sensitive compounds
Mary A. Blanchette,William Choy,Jeffery T. Davis,Amy P. Essenfeld,Satoru Masamune,William R. Roush,Toshiya Sakai +6 more
TL;DR: A mild olefination procedure, utilizing LiCl and an amine, has been developed for use with base-sensitive aldehydes and phosphonates as discussed by the authors.
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Nonlinear Effects in Asymmetric Synthesis and Stereoselective Reactions: Ten Years of Investigation.
Christian Girard,Henri B. Kagan +1 more
TL;DR: Nonlinear effects of an enantiomerically impure catalyst on an asymmetric synthesis are not only of academic interest since they have a variety of practical uses, which are highlighted in this review.
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"Designer acids": combined acid catalysis for asymmetric synthesis.
TL;DR: Combining Lewis and Brønsted acids will bring out their inherent reactivity by associative interaction, and also provide more-organized structures that allow an effective asymmetric environment.
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Basic character of rare earth metal alkoxides. Utilization in catalytic C-C bond-forming reactions and catalytic asymmetric nitroaldol reactions
TL;DR: In this article, the authors reported several carbon-carbon bond-forming reactions catalyzed by rare earth metal alkoxides and their application to a catalytic asymmetric nitroaldol reaction.
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Towards perfect catalytic asymmetric synthesis: dual activation of the electrophile and the nucleophile.
TL;DR: The design and development of new high-performance catalysts for applications in asymmetric catalytic reactions is of ongoing interest in organic chemistry and the dual activation concept greatly broadens the range of artificial catalysts.