Synthesis and Photophysical Properties of β-Alkenyl-Substituted BODIPY Dyes by Indium(III)-Catalyzed Intermolecular Alkyne Hydroarylation.

A new atom-economical synthesis of β-alkenyl-substituted BODIPYs via indium(III)-catalyzed intermolecular alkyne hydroarylation with -substituted BODIPYs is described. While catalysis with InI allows the double β-functionalization of BODIPY, resulting in regioselectively branched β,β'-disubstituted alkenyl BODIPYs, catalytic InCl enables the formation of linear β-substituted alkenyl BODIPYs. Subsequent In(III)-catalyzed intermolecular alkyne hydroarylation allows the synthesis of unsymmetrical - BODIPY derivatives. Therefore, indium catalysis offers complementary regioselectivity in good chemical yields and functional group tolerance. The resulting BODIPY dyes displayed bathochromically shifted absorption and emission according to the electron-nature of the substituents in the alkenyl moiety with high molar extinction coefficients (ε up to 88,200 M cm) and quantum yields (0.14-0.96).