L-amino acid ester as biomimetic reducing agent for the reduction of unsaturated C=C bonds

The first example of an efficient protocol for the reduction of disubstituted methyleneindolinones, isoindigos and tetrasubstituted olefins for the synthesis of 3-substituted 2-oxindoles, dihydroisoindigos and tetrasubstituted ethane derivatives using an L-amino acid ester as an attractive biomimetic reducing agent has been developed. This new protocol has the advantages of mild reaction conditions without the need for any metal catalysts, a broad substrate scope (31 examples), excellent yields (90-98%) and good functional group tolerance, providing an operationally simple and practically useful methodology for reductive reactions. The L-amino acid derivative, which is cheap, nontoxic and easy to handle, serves as a new biomimetic reducing agent for use in organic chemistry, providing a novel and promising approach for future applications in reductive reactions.