Highly Enantioselective Direct Asymmetric Aldol Reaction Catalyzed by 4,5‐Methano‐<i>L</i>‐proline

Abstract

Abstract The 4,5‐methano‐ L ‐proline was used as chiral organocatalysts in direct asymmetric aldol reactions. Under the optimal conditions, excellent enantioselectivities (up to 99% ee ) were obtained with high chemical yields (up to 95%) for a series of aldehydes using only 5 mol% catalyst loading. To show the practicality of the method, the reaction was tested at a large scale. The reaction was complete in 16 h, and the aldol product was obtained in 86% yield and 93% ee .