Photoinduced inverse Sonogashira coupling reaction

Alkynes are widely used in chemistry, medicine and materials science. Here we demonstrate a transition-metal and photocatalyst-free inverse Sonogashira coupling reaction between iodoalkynes and (hetero)arenes or alkenes under visible-light irradiation. Mechanistic and computational studies suggest that iodoalkynes can be directly activated by visible light irradiation, and an excited state iodoalkyne acted as an alkynyl radical synthetic equivalent, reacting with a series of C(sp(2))-H bonds for coupling products. This work should open new windows in radical chemistry and alkynylation method.

Automated summary

This study demonstrates a new transition-metal and photocatalyst-free alkynylation reaction, which allows the coupling of iodoalkynes with (hetero)arenes or alkenes under visible-light irradiation. Mechanistic and computational studies reveal the process of visible light activation of iodoalkynes, and the mechanism of the reaction between the excited state iodoalkyne and C(sp(2))-H bonds to form products.