Autoxidation of acridanyl and benzhydryl carbanions adjacent to sulfur groups leading to C-S bond cleavage with weak chemiluminescence

Autoxidation of acridanyl and benzhydryl carbanions stabilized by sulfur groups gave the corresponding ketones via radical intermediates, being accompanied by a weak light emission. While oxidation of 9-sulfenylacridanes (1a and 1b) in the presence of tert-BuOK showed direct chemiluminescence (CL) due to excited 10-methylacridone, that of benzhydryl phenyl sulfide (2) and benzhydryldimethyl-sulfomium bromide (3) displayed CL in the presence of a fluorescer, 9, 10-dibromoanthracene (DBA), due to excited benzophenone. The yields of excited species in the present oxidation are low but comparable to acyclic peroxide systems. The bimolecular energy transfer from triplet benzophenone to DBA was established in CL of the sulfonium ylide from 3.