A Highly Efficient Base-Metal Catalyst: Chemoselective Reduction of Imines to Amines Using An Abnormal-NHC–Fe(0) Complex

A base-metal, Fe(0)-catalyzed
hydrosilylation of imines to obtain
amines is reported here which outperforms its noble-metal congeners
with the highest TON of 17000. The catalyst, (aNHC)­Fe­(CO)4, works under very mild conditions, with extremely low catalyst
loading (down to 0.005 mol %), and exhibits excellent chemoselectivity.
The facile nature of the imine reduction under mild conditions has
been further demonstrated by reducing imines towards expensive commercial
amines and biologically important N-alkylated sugars, which are difficult
to achieve otherwise. A mechanistic pathway and the source of chemoselectivity
for imine hydrosilylation have been proposed on the basis of the well-defined
catalyst and isolable intermediates along the catalytic cycle.