BF3-catalyzed nucleophilic addition reaction of 1,2-diaminobenzenes with α-ketoesters: Access to cyclic α,α-disubstituted α-amino acid derivatives

Abstract

A metal-free nucleophilic addition reaction of readily available 1,2-diaminobenzenes with α-ketoesters for synthesis of heterocyclic α,α-disubstituted-α-amino acids at room temperature under BF₃·Et₂O catalysis has been accomplished. This transformation occurs smoothly under mild conditions, providing easy access to various heterocyclic α,α-disubstituted-α-amino acids in 54–93 % yields with ample substrate scope, high compatibility of functional groups and easy scale-up. Choosing BF₃·Et₂O as Lewis acid is crucial for the success of this transformation.