A novel photoinduced thioselenation of allenes by use of a disulfide-diselenide binary system

Dependent on the selection of the lights employed, the relative.reactivities of organic dichalcogenides toward carbon radicals, and the thermodynamical stability of products, it has become apparent that two different chalcogeno groups can be introduced simultaneously into allenes with excellent selectivity. The (PhS)(2)-(PhSe)(2) binary system is effective for the regioselective thioselenation of allenes, affording beta-selenoallylic sulfides in good yields. Further investigation on the reaction of allenes with (PhS)(2) and (PhTe)(2) afforded no thiotelluration products, unfortunately, due to the instability of C-Te bonds under photoirradiated conditions. However, a novel telluride-catalyzed dithiolation reaction of allenes with disulfides has been developed successfully, while the use of a disulfide single system could not effect the radical dithiolation of allenes.