Highly effective synthetic methods for substituted 2-arylbenzofurans using [3,3]-sigmatropic rearrangement: short syntheses of stemofuran a and eupomatenoid 6.

A new and efficient synthesis of 2-arylbenzofurans has been achieved via a route involving acylation and subsequent [3,3]-sigmatropic rearrangement of oxime ethers. Its synthetic utility is demonstrated by a short synthesis of stemofuran A and eupomatenoid 6 in which no procedure for protection of the phenolic hydroxyl groups is needed. [reaction--see text]