Monoamine Oxidase (MAO-N) Biocatalyzed Synthesis of Indoles from Indolines Prepared via Photocatalytic Cyclization/Arylative Dearomatization

The biocatalytic aromatization of indolines into indole derivatives exploiting monoamine oxidase (MAO-N) enzymes is presented. Indoline substrates were prepared via photocatalytic cyclization of arylaniline precursors or via arylative dearomatization of unsubstituted indoles and in turn chemoselectively aromatized by the MAO-N D11 whole cell biocatalyst. Computational docking studies of the indoline substrates in the MAO-N D11 catalytic site allowed for the rationalization of the biocatalytic mechanism and experimental results of the biotransformation. This methodology represents an efficient example of biocatalytic synthesis of indole derivatives and offers a facile approach to access these aromatic heterocycles under mild reaction conditions.