Catalyst-controlled switchable formal retro-Büchner reaction for the divergent synthesis of benzo[b]azepines and 1, 3-conjugated dienes

Abstract

Herein, a phosphine catalyst-controlled switchable formal retro-Büchner reaction of MBH carbonates with N-sulfonyl azaheptafulvenes has been successfully developed, which provides a divergent and efficient route to access valuable benzo[b]azepine and multiple substituted 1, 3-conjugated diene derivatives in moderate to great yields. Additionally, these methodologies are characterized by mild reaction conditions, absence of transition metal, easy operation, broad functional-group tolerance, and amenability to gram-scale synthesis.