Concise strategy for diastereoselective annulation to afford fused [5:7] oxazepanone γ-lactams

Abstract

A series of novel potentially biologically active fused [5:7] oxazepanone γ-lactams were synthesized and described. A series of functional group transformations, namely amination, syn-hydrogenation and intramolecular annulation reactions were used to obtain the [5:7] oxazepanone γ-lactams in reasonable yields. In the diastereoselective fused-annulation for the formation of the secondary ring, steric constrain and cisgeometrical configuration of C-3 and C-4 substituents were observed as the predetermined factors. These ring annulations were purposely constructed to suit the physicochemical enhancement of the biological activity of the title compounds via SAR study of γ-lactams.