Thiaheterohelicenes 2. Synthesis of alkylated thiaheterohelicenes

Abstract

The alkylated thiaheterohelicenes 1,2,3,4,6,7,9,10,11,12-decamethl-5,8-dithia[5]-helicene 1 and 6,7,9,10,12,13-hexamethl-5,8,11,14-tetrathia[9]helicene 2 have been prepared by oxidative photolysis of 1,2-diaryl-substituted ethenes. The symmetrical ethenes used in the procedures were prepared by McMurry coupling. Unsymmetrical tetrasubstituted ethenes were obtained by nucleophilic addition of lithium arylates to 3-arylbutan-2-one and dehydration. © Acta Chemica Scandinavica 1996.