Photomediated core modification of diaryl dihydrophenzines through three-component alkylarylation of alkenes toward organocatalyzed ATRP

Abstract

The design and synthesis of a novel organic photocatalyst (OPC) have attracted broad interest from both the organic chemistry and polymer community. Herein, we presented a visible-light-induced alkylarylation of alkenes strategy for core modification of 5,10-diaryl-5,10-dihydrophenazines (DADHPs) under metal- and additive-free conditions, with the aim to develop powerful photocatalyst for organocatalyzed atom transfer radical polymerization (O-ATRP). Good tolerance for a wide variety of functional groups and affording the corresponding tetrasubstituted products in moderate to good yields were achieved in the batch and flow reactor. The experimental and computational mechanistic study confirmed that DADHPs’ radical cations and π-π stacking interactions played important roles in the alkylarylation of alkenes. A series of the tetrasubstituted DADHPs were directly synthesized from the corresponding noncore-modified phenazines, which were demonstrated to be effective organic photoredox catalysts for O-ATRP. Light responsive nature, controlled polymerization manner, and well-defined poly (methyl methacrylate) were achieved via tetrasubstituted DADHPs mediated O-ATRP.