Photoinduced reactions of 1,3,4(2H)-isoquinolinetriones with diphenylacetylenes—an efficient one pot syntheses of dibenz[de,g]-(2H)-isoquinoline-4,6-dione derivatives

Photoinduced reactions of 1,3,4(2H)-isoquinolinetriones with diphenylacetylenes afforded the corresponding dibenz[de,g]-(2H)-isoquinoline-4,6-dione derivatives in moderate to high yields via a reaction sequence involving [2+2] photocycloaddition, ring opening rearrangement of the oxetene intermediate and dehydrogenative cyclization in one pot.