Gold-Catalyzed N,O‑Functionalizations of 6‑Allenyl-1-ynes with N‑Hydroxyanilines To Construct Benzo[b]‑azepin-4-one Cores

Gold-catalyzed reactions of 6-allen-1-ynes with N-hydroxyanilines afford thermally stable benzoazepin-4-ones in anti-selectivity; these anti-configured products are easily isomerized to their syn-isomers on a silica column. The mechanism of reactions likely involve initial nitrone/allene cycloadditions, followed by skeletal rearrangement of resulting intermediates.