Cyclization and Fragmentation of N-Chloro Lactams. The Transannular Synthesis of Bicyclic Lactams with Bridgehead Nitrogen

Abstract

High yield peroxide initiated and photochemical conversion of N-chloroazacyclooctanone to 5-chloroazacyclooctanone and of N-chloroazacyclononanone to a mixture of azabicyclo[4.3.0]nonan-2-one and azabicyclo[4.3.0]nonan-9-one is described. N-Chloro-2-azabicyclo[2.2.2]octan-3-one gave 4-chlorocyclohexylamine derivatives under similar conditions, while N-chloro-N-methylpentanoamide gave γ-valerolactone. An apparent ionic, silver ion, and base-catalyzed cyclization of N-chloroazacyclononanone was observed.