Direct preparation of benzofurans from O-arylhydroxylamines.

Reaction of O-arylhydroxylamine hydrochlorides with either cyclic or acyclic ketones in the presence of methanesulfonic acid leads directly to the benzofuran deriv. via a proposed one-pot condensation-rearrangement-cyclization reaction sequence in good to excellent yields. E.g., in the presence of methanesulfonic acid, reaction of H2NOPh.HCl and cyclohexanone gave 70% benzofuran deriv. I