α-Amination of 1,3-Dicarbonyl Compounds and Analogous Reactive Enolate-Precursors Using Ammonia Under Oxidative Conditions

Abstract

We herein introduce a method for the direct a-amination of different carbonyl compounds by employing aqueous ammonia as the N-source. Upon using NH3 in combination with hypochlorites as simple oxidants under phase-transfer catalytic conditions it is possible to carry out the direct a-amination of reactive enolate-precursors such as cyclic b-ketoesters, oxindoles, as well as malonitriles and malonates with good to excellent yields, while simple ketone precursors being out of the scope thus far. Furthermore, a first proof-of-concept for an asymmetric variant by employing a chiral quaternary ammonium salt is reported.