Aminoborohydrides. 12. Novel tandem S(N)Ar amination-reduction reactions of 2-halobenzonitriles with lithium N,N-dialkylaminoborohydrides.

S Thomas, C J Collins, J R Cuzens, D Spiciarich, C T Goralski, B Singaram

Index: J. Org. Chem. 66(6) , 1999-2004, (2001)

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Abstract

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