L-proline-catalyzed activation of methyl ketones or active methylene compounds and DMF-DMA for syntheses of (2E)-3-dimethylamino-2-propen-1-ones

Abstract

A cascade organocatalysis is reported for the nucleophilic and electrophilic dual activation taking place in the reaction of methyl ketones or active methylene compounds with DMF-DMA (N,N-dimethylformamide dimethyl acetal). L-Proline serves as an efficient organocatalyst in the covalent and noncovalent synchronous mode for the ambiphilic activation of various aryl, heteroaryl, and styryl methyl ketones, cyclic ketones, and 1,3-diketones with DMF-DMA to achieve the convenient syntheses of the versatile synthons (2E)-1-aryl/heteroaryl/styryl-3-(dimethylamino)-2-propen-1-ones, (E)-α-[(dimethylamino)formylidene]cycloalkanones, and (E)-2-(dimethylamino)formylidene-1,3-diketones in high yields under solvent-free conditions.