Design, Synthesis, and Organocatalytic Activity of N-Heterocyclic Carbenes Functionalized with Hydrogen-Bond Donors in Enantioselective Reactions of Homoenolates

A focused library of chiral imidazolinium salts functionalized with urea‐type hydrogen‐bond donor moieties has been prepared from the chiral pool. The corresponding N‐heterocyclic carbenes were evaluated as organocatalysts in three enantioselective reactions involving homoenolate intermediates gener...

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Bibliographic Details
Published in:European journal of organic chemistry 2013-12, Vol.2013 (36), p.8253-8264
Main Authors: Nawaz, Faisal, Zaghouani, Mehdi, Bonne, Damien, Chuzel, Olivier, Rodriguez, Jean, Coquerel, Yoann
Format: Article
Language:English
Subjects:
Carbenes
Chemical Sciences
Enantioselectivity
Hydrogen bonds
Organic chemistry
Organocatalysis
Umpolung
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Summary:A focused library of chiral imidazolinium salts functionalized with urea‐type hydrogen‐bond donor moieties has been prepared from the chiral pool. The corresponding N‐heterocyclic carbenes were evaluated as organocatalysts in three enantioselective reactions involving homoenolate intermediates generated from enals. The catalysts proved competent in enantioselective cyclopentannulation and γ‐lactonization reactions, a premiere for imidazoline‐based NHCs. This work conveys some new ideas and knowledge on the concepts of bifunctional enantioselective organocatalysis applied to NHCs. Chiral 1,3‐imidazolin‐2‐ylidene NHCs functionalized with urea‐type hydrogen‐bond donors have been evaluated as organocatalysts in enantioselective reactions of homoenolates. Some unprecedented levels of enantioselectivity have been obtained.
ISSN:1434-193X
1099-0690
DOI:10.1002/ejoc.201301366