Hexahydro-1,4-oxazepines. Part 1. Synthesis by morpholine ring expansion
Abstract
Reaction of 4-benzyl-3-chloromethylmorpholine with phenoxide anions led not only to 4-benzyl-3-phenoxymethyl morpholines, but substantial amounts of 4-benzyl-6-phenoxy-1,4-oxazepanes. The ring expansion reaction is explained in terms of neighbouring group participation, leading to an ambident aziridinium cation intermediate.