Highly diastereoselective asymmetric Mannich reactions of 1,3-dicarbonyls with acyl imines.
[reaction: see text] The cinchona alkaloids catalyze direct asymmetric Mannich reactions of cyclic 1,3-dicarbonyl compounds with acyl imines to afford alpha-quaternary carbon-bearing reaction products in yields of up to 98%, a diastereomeric excess of 90% or greater, and enantioselectivities up to 99% ee. A model is proposed that accounts for both the observed diastereoselectivities and the enantioselectivities for the reactions.
Ting
Amal
A
Department of Chemistry, Center for Chemical Methodology and Library Development at Boston University, Massachusetts 02215, USA.
Lou
Sha
S
Schaus
Scott E
SE