Azepines and their Fused-ring Derivatives

Abstract

Azepines and their benz-fused derivatives have commanded a considerable amount of synthetic interest. This is particularly true of the latter systems because of their continuing pharmacological significance. Ring synthesis by ring construction is the dominant general approach, although a number of new ring transformation strategies have been developed. Amongst the ring construction strategies a flowering of methods based on ring closing metathesis is evident for type c and type d processes. There is scope also for extension of this methodology to type b processes. A novel zirconium-mediated approach to substituted azepanes has been described and this reaction has considerable further synthetic potential. The synthetic power of sequential reactions has also been demonstrated, for example in the synthesis of tetrahydro-1H-1-benzazepine derivatives. A single crystal X-ray structure of the first reported 2-azatropone is also a significant development.