Enantioselective Radical Addition to Heteroarenes

Key words

iridium catalysis - photocatalysis - Brønsted acids - Minisci-type reaction - heteroarenes

Significance

Heteroarenes with basic nitrogen centers, such as pyridines or quinolines, can be found in pharmaceuticals and in bioactive molecules. Minisci-type reactions are direct methods to synthesize such classes of compounds, but the generation of highly enantioselective stereocenters is challenging. The authors have developed a highly enantio- and regioselective addition of α-amino alkyl radicals to pyridines and quinolines in the presence of an iridium photoredox catalyst and a chiral Brønsted acid catalyst.

Comment

The chiral Brønsted acid activates the heteroarene and induces the enantioselectivity of the reaction, whereas the iridium photoredox catalyst plays a role in the electron-transfer process. In addition to being applicable to a broad scope of substrates, the reaction can be used in late-stage functionalizations of molecules in a highly chemo-, regio-, and enantioselective manner.