A Highly Efficient Large-Scale Asymmetric Direct Intermolecular Aldol Reaction Employing L-Prolinamide as a Recoverable Catalyst

A new, simple bifunctional, recoverable and reusable L-prolinamide organocatalyst that promotes aldol reactions while achieving a respectable level of enantioselectivity is reported. This organocatalyst is applicable to the reactions of a wide range of aromatic and heteroaromatic aldehydes with cyclic and acyclic ketones, and the anti-aldol products could be obtained with up to 99:1 anti/syn ratio and 98% ee. The catalyst can be easily recovered and reused, and only a slight decrease of enantioselectivity was observed for five cycles. This novel catalyst can be efficiently used in large-scale reactions with the enantioselectivity being maintained at the same level, which offers a great possibility for application in industry.