Visible-Light-Induced [1+5] Annulation of Phosphoryl Diazomethylarenes and Pyridinium 1,4-Zwitterionic Thiolates.

Visible-light-induced [1+5] annulation of phosphoryl diazomethylarenes and pyridinium 1,4-zwitterionic thiolates generates various trifunctionalized dialkyl 1-phosphoryl-1,9a-dihydropyrido[2,1- c ][1,4]thiazine-3,4-dicarboxylates in good to excellent yields and diastereoselectivities. The annulation involves the nucleophilic attack of thiolates on diazomethylarene-generated carbenes followed by an intramolecular cyclization, is free of catalysts, is atom-economical, and has mild reaction conditions.