NHC-catalyzed covalent activation of heteroatoms for enantioselective reactions
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TLDR
Covalent activation of heteroatoms enabled by N-heterocyclic carbene (NHC) organic catalysts for enantioselective reactions is evaluated and summarized in this review.Abstract:
Covalent activation of heteroatoms enabled by N-heterocyclic carbene (NHC) organic catalysts for enantioselective reactions is evaluated and summarized in this review. To date, sulfur, oxygen, and nitrogen atoms can be activated in this manner to react with another substrate to construct chiral carbon–heteroatom bonds with high optical enantioselectivities. The activation starts with addition of an NHC catalyst to the carbonyl moiety (aldehyde or imine) of substrates that contain heteroatoms. The key in this approach is the formation of intermediates covalently bound to the NHC catalyst, in which the heteroatom of the substrate is activated as a nucleophilic reactive site.read more
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Tale of the Breslow intermediate, a central player in N-heterocyclic carbene organocatalysis: then and now.
TL;DR: The Breslow intermediate as discussed by the authors is formed by the nucleophilic addition of an NHC to a carbonyl group of a suitable electrophile, and it has been shown that a direct 1,2-proton transfer within the initial zwitterionic intermediate is energetically prohibitive and hence the participation of other species capable of promoting an assisted proton transfer is more likely.
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Generation of azolium dienolates as versatile nucleophilic synthons via N-heterocyclic carbene catalysis
TL;DR: In this review, the recent advances in NHC-catalyzed generation of azolium dienolates from different precursors and their applications in the synthesis of various valuable molecules are summarized comprehensively.
Journal ArticleDOI
Regiodivergent Organocatalytic Reactions
Mayavan Viji,Srinu Lanka,Jaeuk Sim,Chanhyun Jung,Heesoon Lee,Manjunatha Vishwanath,Jae-Kyung Jung +6 more
TL;DR: A review of recent advances in regiodivergent reactions that are governed by organocatalysts can be found in this paper, where the authors briefly discuss the reaction pathways of achieving regioselective products by changes in conditions such as solvents, additives, or temperature.
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Theoretical study of the NHC-catalyzed C–S bond cleavage and reconstruction reaction: mechanism, stereoselectivity, and role of catalysts
TL;DR: A theoretical study of the mechanism of the N-heterocyclic carbene (NHC)-catalyzed C-S bond cleavage and reconstruction reaction of unsaturated thioesters was conducted using density functional theory as mentioned in this paper.
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Unraveling the mechanism and substituent effects on the N-heterocyclic carbene-catalyzed transformation reaction of enals and imines
TL;DR: In this article , an intramolecular hydrogen bond-promoted activation of imines represents a new strategy in annulation reactions catalyzed by N-heterocyclic carbenes (NHCs).
References
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