Gold-catalyzed cyclization of 1,6-diynyl dithioacetals via 1,7-carbene transfer and aromatic C–H functionalization

Abstract

A gold-catalyzed cyclization of 1,6-diynyl dithioacetals has been developed, which provides an attractive route to diverse-substituted benzo[a]fluorene derivatives. The reaction is initiated through 1,2-sulfur migration of a propargyl dithioacetal moiety to generate a vinyl gold carbene, which is followed by carbene transfer to the remaining alkyne and aromatic substitution to furnish the fused products in generally good to high yields.