Enantioselective Organocatalytic Approach to α-Methylene-δ-lactones and δ-Lactams

We present the first enantioselective organocatalytic approach for the synthesis of alpha-methylene-delta-lactones and delta-lactams. Our methodology utilizes the Michael addition of Unmodified aldehydes to ethyl 2-(diethoxyphosphoryl)acrylate as the key step affording highly enantiomerically enriched adducts, which can be transformed into the target Compounds maintaining the high stereoselectivity achieved in the first step. This methodology has been shown to be general and various optically active gamma-substituted alpha-methylene-delta-lactones and delta-lactams can be easily accessed.