Gram-Scale Synthesis of the N-Phenyl Phenothiazine Photocatalyst by Benzyne Addition



N-phenyl phenothiazine is one of the most reducing photoredox catalysts. Its synthesis commonly requires transition metal catalyzed cross-coupling reactions. Here we show the syntheses of four aryl phenothiazines via a benzyne route, including a multi-gram scale synthesis of N-phenyl phenothiazine. While yields are modest, the simplicity, low cost, and lack of requirement for cross-coupling catalyst in this synthesis will be attractive to users of this photocatalyst.


Thumbnail image of Phenothiazine draft 4 RXIV.pdf

Supplementary material

Thumbnail image of PTC SI RXIV.pdf
Supporting Information
Synthetic Procedures, X-Ray Data, NMR Spectra