Asymmetric Ion-Pairing Photoredox Catalysis for Stereoselective Cationic Polymerization under Light Control.

By virtue of noninvasive regulations by light, photocontrolled polymerizations have attracted considerable attention for the precision synthesis of macromolecules. However, a cationic polymerization with simultaneous photocontrol and tacticity-regulation remains elusive so far. Herein, we introduce an asymmetric ion-pairing photoredox catalysis strategy that allows for the development of a stereoselective cationic polymerization with concurrent light regulation for the first time. By employing an ion pair catalyst (PC + /*A - ) consisting of a photoredox active cation (PC + ) and a sterically confined chiral anion (*A - ) to deliver the stereochemical control, the cationic polymerization of vinyl ethers can be achieved with photocontrol and high isotactic selectivity (up to 91% m ) at a remarkable low catalyst loading (50 ppm).