STEREOSELECTIVE SYNTHESIS OF VINYL ETHERS BY THE REACTION OF N-(ARYLIDENE(OR ALKYLIDENE)AMINO)-2-AZETIDINONES WITH OZONE

Ozonolysis of N-(arylidene(or alkylidene)amino)-2-azetidinones followe d by NaBH4 workup yields enol ethers in good yields with high levels o f stereoselectivity. Di- and trisubstituted olefin derivatives are ava ilable through this procedure. Chiral 2-azetidinones lead to enol ethe rs with a chiral moiety without racemization. The reaction is thought to occur through a novel B-type fragmentation of the 2-azetidinone rin g. This process is closely related to the well-known N-nitrosoamide to ester rearrangement and the decarboxylation of oxetan-2-ones.