Aminoborohydrides. 12. Novel tandem SNAr amination-reduction reactions of 2-halobenzonitriles with lithium N,N-dialkylaminoborohydrides

A novel tandem amination-reduction reaction has been developed in which 2-( N,N-dialkylamino)benzylamines are generated from 2-halobenzonitriles and li thium N, N-dialkylaminoborohydride (LAB) reagents. These reactions are beli eved to occur through a tandem SNAr amination-reduction mechanism wherein t he LAB reagent promotes halide displacement by the N,N-dialkylamino group, and the nitrile is subsequently reduced. This one-pot procedure is complime ntary to existing synthetic methods and is an attractive synthetic tool for the nucleophilic aromatic substitution of halobenzenes with less nucleophi lic amines. The (N,N-dialkylamino)benzylamine products of this reaction are easily isolated after a simple aqueous workup procedure in very good to ex cellent yields.