Reactions of Benzyl Phosphine Oxide/Sulfide with (COCl): Synthesis of Novel Acyl Chloride-Substituted Chlorophosphonium Ylides.

New reactions of benzyl phosphine oxide/sulfide with oxalyl chloride are presented. The resulting reactive intermediates, acyl chloride-substituted chlorophosphonium ylides, are capable of undergoing esterification and Friedel-Crafts acylation reactions, ultimately yielding either methyl 2-(2-bromophenyl)-2-(diphenylphosphoryl)acetate or β-carbonyl-diarylphosphine oxide derivatives. Additionally, when an alkynyl group is contained in the acyl chloride-substituted chlorophosphonium ylide, intramolecular cyclization occurs, leading to the formation of a pair of and dichlorophosphonyl benzofulvene isomers. The generation process of acyl chloride-substituted chlorophosphonium ylide was carefully monitored by using P{H} NMR spectroscopy, and a plausible reaction mechanism was proposed.