Fe-catalyzed reduction of aldimines with HBpin

We develop an efficient and workable method for the reduction of imines via hydroboration with HBpin. The low cost and non-toxic Fe exhibits high catalytic activity to this hydroboration. A large range of aldimines comprising diverse aryl groups, alkyl groups and heterocycles proceed the hydroboration well to yield secondary amines in good to excellent yields. Kinetic mechanistic studies indicate the importance of Fe in transformation of HBpin into an active species. The preparation of several commercially available pharmaceuticals by means of this strategy highlights its potential application in medicinal chemistry.