Visible Light-induced regioselective bifunctionalization of α-olefin; Development of one-pot photo-synthesis of C3-substituted dihydrobenzofurans

A method for the catalytic regioselective synthesis of C3-substituted dihydrobenzofurans (DHBs) via [2+2] photocycloaddition of alkene and p-benzoquinone is developed. This method realizes the rapid synthesis of DHBs with readily available substrates and simple reaction conditions by using Lewis acid B(C6F5)3 and Lewis base P(o-tol)3 as a catalyst in combination with the classical Paternò–Büchi reaction. This reaction is of interest in terms of bifunctionalization by formal [2+3] cycloaddition of olefins and applies to a wide range of a-olefins.