Efficient reductions of dimethylhydrazones using preformed primary amine boranes

A convenient method for the reduction of N,N-dimethylhydrazones using amine borane complexes generated in situ is described. It was found that primary amine borane complexes performed exceedingly well at reducing N,N-dimethylhydrazones in as little as 1.1 equivalents, furnishing the corresponding air-sensitive hydrazine products in excellent yields.