Synthesis of trans-disubstituted-2,3-dihydrobenzofurans by a formal [4 + 1] annulation between para-quinone methides and sulfonium salts

Abstract

An efficient protocol for the synthesis of trans-disubstituted-2,3-dihydrobenzofurans through [4 + 1] annulation of para-quinone methides with sulfonium salts has been developed. Under very mild conditions this unprecedented reaction occurs in good to excellent yields (up to 99%), offering a straightforward access to a variety of 2,3-dihydrobenzofurans.