Enantioselective organocatalytic conjugate addition of aldehydes to nitrodienes.
The asymmetric organocatalyzed Michael addition of aldehydes to alpha,beta-gamma,delta-unsaturated nitro compounds has been accomplished using only 5 mol % of (S)-diphenylprolinol silyl ether and 2 equiv of aldehyde in a mixture of ethanol and water (5% v/v). The Michael adducts were obtained in good yields, diastereoselectivities up to 94/6, and ee's up to 99%. This process provides synthetically useful compounds which can easily lead to more complex molecules, as exemplified with substituted tetrahydropyran or cyclohexene.
Belot
Sébastien
S
Department of Organic Chemistry, University of Geneva, 30, quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland.
Massaro
Assunta
A
Tenti
Alice
A
Mordini
Alessandro
A
Alexakis
Alexandre
A