Visible-Light-Induced Reductive Coupling of Arylacetylenes with Benzothiazole Sulfones

In this study, we propose heavy-metal-free reductive coupling of arylacetylenes with benzothiazole sulfones. The reactions of alkyl or benzylic benzothiazole sulfones with arylacetylenes are successfully performed in the presence of Hantzsch esters and K2CO3 under visible-light irradiation to afford 1,2-disubstituted alkenes in moderate to good yields, with Z-isomer as the major product. The utility of this protocol is expanded to a-deuterative coupling using a deuterated Hantzsch ester, furnishing the corresponding alkenes with high deuterium incorporation.

Automated summary

In this study, a heavy-metal-free reductive coupling reaction of arylacetylenes with benzothiazole sulfones is proposed. The reaction of alkyl or benzylic benzothiazole sulfones with arylacetylenes is successfully achieved under visible-light irradiation in the presence of Hantzsch esters and K2CO3, giving moderate to good yields of 1,2-disubstituted alkenes with Z-isomer as the major product. The utility of this method is further expanded to a-deuteration coupling reaction using a deuterated Hantzsch ester, leading to the corresponding alkenes with high deuterium incorporation.