Phenylphenothiazine-Based Porous Organic Polymers as Visible-Light Heterogeneous Photocatalysts for Switchable Bromoalkylation and Cyclopropanation of Unactivated Terminal Alkenes

We report the design and synthesis of porous organic polymers (POPs) based on N-phenylphenothiazine (PTH), which typically requires ultraviolet-light irradiation, as a class of purely organic, stable, and reusable visible-light heterogeneous photocatalysts. The extended π-conjugation and polymeric networks not only enhance visible-light absorption but also accelerate the reaction rates. More intriguingly, the switchable bromoalkylation and cyclopropanation of unactivated terminal alkenes could be achieved by simply tuning the solvents under PTH-POP catalysis. The flexible manipulation of the resultant products further demonstrates its synthetic utility.