Synthesis of 2,5-disubstituted dihydrofuran-3(2 H)-ones via [2,3]-sigmatropic rearrangement of oxonium ylides generated from α-oxo gold carbenes

Novel [2,3]-sigmatropic rearrangements of oxonium ylides generated from α-oxo gold carbenes were discovered. An efficient synthetic method of 2,5-disubstituted dihydrofuran-3(2H)-ones via gold-catalyzed intermolecular oxidation of the allyl homopropargyl ethers with N-oxide was developed. And the synthetic utility of the current method has been proved by concise formal synthesis of (±)-kumausallene.