Stereoselective synthesis of unnatural α-amino acid derivatives through photoredox catalysis

Andrey Shatskiy; Anton Axelsson; Elena V Stepanova; Jian-Quan Liu; Azamat Z Temerdashev; Bhushan P Kore; Björn Blomkvist; James M Gardner; Peter Dinér; Markus D Kärkäs

doi:10.1039/d1sc00658d

Stereoselective synthesis of unnatural α-amino acid derivatives through photoredox catalysis

Chem Sci. 2021 Mar 3;12(15):5430-5437. doi: 10.1039/d1sc00658d.

Authors

Affiliations

¹ Division of Organic Chemistry, Department of Chemistry, KTH Royal Institute of Technology SE-100 44 Stockholm Sweden karkas@kth.se.
² Tomsk Polytechnic University Lenin Avenue 30 634050 Tomsk Russia.
³ Zelinsky Institute of Organic Chemistry of the Russian Academy of Sciences Leninsky Prospect 47 119991 Moscow Russia.
⁴ Department of Analytical Chemistry, Kuban State University Stavropolskaya St. 149 350040 Krasnodar Russia.
⁵ Division of Applied Physical Chemistry, Department of Chemistry, KTH Royal Institute of Technology SE-100 44 Stockholm Sweden.

Abstract

A protocol for stereoselective C-radical addition to a chiral glyoxylate-derived N-sulfinyl imine was developed through visible light-promoted photoredox catalysis, providing a convenient method for the synthesis of unnatural α-amino acids. The developed protocol allows the use of ubiquitous carboxylic acids as radical precursors without prior derivatization. The protocol utilizes near-stoichiometric amounts of the imine and the acid radical precursor in combination with a catalytic amount of an organic acridinium-based photocatalyst. Alternative mechanisms for the developed transformation are discussed and corroborated by experimental and computational studies.