Conjugation‐Driven Cascade Approach to Enantiopure Pyrano‐Fused 1,5‐Benzodiazepines by Tandem Condensation/[3,3]‐Sigmatropic Rearrangement/Aza‐Michael Addition–Elimination

Abstract

Sugar‐based Morita–Baylis–Hillman (MBH) acetates easily obtained from commercially available D‐glucal underwent rapid reaction with 1,2‐benzenediamines to give, in good yields, a series of enantiomerically pure tricyclic pyrano‐fused 1,5‐benzodiazepines with multiple points of diversity, which could serve as potential drug scaffolds. The driving force behind this reaction seemed to be the high stability associated with the conjugated tricyclic system. The reaction involved an unprecedented amine–carbonyl condensation/[3,3]‐sigmatropic rearrangement/cyclization cascade.