The Synthesis\nof Benzazepines via Sequential [3 +\n2]-Annulation and [3,3]-Sigmatropic Rearrangement

A novel annulation reaction of prop-2-ynylsulfonium salts\nwith\nsulfur ylides and nitrosobenzenes has been developed, affording various\nbenzazepines in moderate to good yields. Prop-2-ynylsulfonium salts\nact as C<sub>3</sub> synthons in the reactions, providing a promising\nbenzazepine skeleton in a one-pot operation with readily accessible\nstarting materials.