Formation of quaternary chiral centers by N-heterocyclic carbene-Cu-catalyzed asymmetric conjugate addition reactions with Grignard reagents on trisubstituted cyclic enones.
The copper-catalyzed conjugate addition of Grignard reagents to 3-substituted cyclic enones allows the formation of all-carbon chiral quaternary centers. We demonstrate in this article that N-heterocyclic carbenes act as efficient chiral ligands for this transformation. High enantioselectivities (up to 96% ee) could be obtained for a variety of substrates.
Département de Chimie Organique, Université de Genève, 30 quai Ernest-Ansermet, 1211 Genève-4, Switzerland.
Stefan
S
Kehrli
David
D
Martin
Diane
D
Rix
Marc
M
Mauduit
Alexandre
A
Alexakis