L-Proline-Catalyzed Activation of Methyl Ketones or Active Methylene Compounds and DMF-DMA for Syntheses of (2E)-3-Dimethylamino-2- propen-1-ones

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. A covalent and noncovalent synchronously ambiphilic activation of methyl ketones or active methylene compounds with DMF‐DMA (N,N‐dimethylformamide dimethyl acetal) by L‐proline for the syntheses of (2E)‐3‐dimethylamino‐2‐propen‐1‐ones is described.