Photocontrolled Stereoselective Cationic Polymerization

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 photo-control and tacticity-regulation remains elusive and challenging to achieve. Herein, we introduce an asymmetric ion-pairing photoredox catalysis strategy, which allows for the development of a stereoselective cationic polymerization with light control for the first time. By employing a chiral ion pair photoredox catalyst (PC+/*A–) con-sisting of a photoredox active cationic part (PC+) and a sterically confined chiral anion (*A–) to deliver the stereochemical control, the stereoselective cationic polymerization of vinyl ethers with the assistance of photo control can be achieved with high isotactic selectivity (up to 91% m) at a remarkable low level of catalyst loading (50 ppm).