1,6-Conjugated addition-mediated [4 + 1] annulation: an approach to 2,3-dihydrobenzofurans†
Abstract
A formal 1,6-conjugated addition-mediated [4 + 1] annulation of ortho-hydroxyphenyl-substituted para-quinone methides with sulfonium or ammonium bromides has been described. This domino-type process offered an efficient method for the synthesis of 2,3-dihydrobenzofurans in good yields, exhibiting good functional group tolerance, scalability and high diastereoselectivity.