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 α-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 α-amination of reactive enolate-precursors such as cyclic β-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.