Synthesis of (Z)-1,2-dihydro-1-tosylbenzo[b]azepin-3-ones by two-step, one-pot gold-catalyzed tandem heterocyclization/Petasis–Ferrier rearrangement of 2-(N-(prop-2-ynyl)-N-tosylamino)benzaldehydes

A two-step, one-pot synthetic method that relies on gold(I)-catalyzed tandem heterocyclization/Petasis–Ferrier rearrangement and Brønsted acid-assisted debenzoxylation of 2-(N-(prop-2-ynyl)-N-tosylamino)benzaldehydes to prepare (Z)-1,2-dihydro-1-tosylbenzo[b]azepin-3-ones efficiently is reported. The reactions proceed rapidly under mild and operationally straightforward conditions for a wide variety of aldehyde substrates containing electron-withdrawing, electron-donating, and sterically demanding functional groups and afforded the corresponding benzo-fused azaheterocyclic products in moderate to excellent yields.