A photochemically-generated acyl–vinyloxy biradical as a synthetic precursor of a 2,3-dihydrofuran and a butyrolactone
Abstract
Photolysis of 4,4,7,7-tetramethyl-4,6,7,8-tetrahydro-2H-1-benzopyran-2,5(3H)-dione (1) gives the acyl–vinyloxy biradical (4) which can be trapped with oxygen to give the spirolactone (3) before losing CO to form the 2,3-dihydrofuran (2).