Gold(iii)-catalyzed synthesis of aroylbenzo[b]oxepin-3-ones from ortho-O-propargyl-1-one substituted arylaldehydes.

An efficient gold-catalyzed intramolecular cyclization of ortho-O-propargyl-1-one substituted arylaldehydes has been achieved for the generation of substituted aroylbenzo[b]oxepin-3-one derivatives in moderate to good yields. This synthetic transformation proceeds via gold-catalysed oxidation of the internal alkyne moiety followed by an intramolecular condensation leading to seven-membered oxacycles.