Oxazoline-Substituted Prolinamide-Based Organocatalysts for the Direct Intermolecular Aldol Reaction between Cyclohexanone and Aromatic Aldehydes

Abstract:

Oxazoline-substituted prolinamides catalyse the direct asymmetric aldol reaction between cyclohexanone and a range of aldehydes to give excellent conversions and enantioselectivities up to 84% under optimum conditions. Reactions were highly substrate-specific with electron-deficient aldehydes giving the highest yields and ee values. The absolute configuration of the 4-chlorobenzaldehyde-derived product was unequivocally established as (2S,1R) by single-crystal X-ray analysis, and the stereochemistry of the product was shown to be determined principally by the stereochemistry of the proline fragment.