Benzothiazolines, with their versatile nature, serve
as fundamental
building blocks for the synthesis of significant biological compounds.
However, methods for the preparation of benzothiazolines from readily
available starting materials are limited. An efficient synthesis of
benzothiazoline via photoredox-catalyzed dearomatization of benzothiazole
derivatives has been achieved at room temperature. This catalysis
proceeds via a ligand to metal charge transfer process, and FeCl3 plays a dual role as an indirect HAT reagent and reducing
agent. This methodology can be conveniently scaled up, and most of
the alkylated products can be purified without chromatography. In
addition, this process exhibited the advantages of low cost, high
reaction efficiency, and mild conditions