Construction of C-S and C-Se Bonds via Photocatalytic Aromatization-Driven Deconstructive Diversification of Spiro-Dihydroquinazolinones Derived from Unstrained Ketones.

A novel and robust deconstructive functionalization reaction of spiro-dihydroquinazolinones with sulfenylating reagents in the presence of base has been realized under visible light irradiation. This reaction enabled the direct ring-opening of unstrained cyclic ring systems, producing skeletally diverse functionalized quinazolinones with moderate to good yields. A range variety of sulfenylating reagents including diaryl disulfide, thiosulfonate, dithiosulfonate and 1-[(trifluoromethyl)thio]-2,5-pyrrolidinedione were compatible for this transformation. In addition, diaryl diselenide and selenosulfonate could also couple with spiro-dihydroquinazolinones to form C-Se Bonds. Mechanistic studies revealed that the reaction proceeds via a radical-radical coupling pathway.