8.02 Reduction of C[dbnd]N to CH–NH by Metal Hydrides

Abstract

The reduction of imines to amines [(CN) to CH–NH] is a fundamental reaction in the synthesis of amines and amine derivatives. The recent years have witnessed the development of several new advancements in the reduction of imines and N-substituted imines to primary, secondary, and tertiary amines and N-substituted amines with metal hydrides. This chapter addresses two kinds of reductions: the reduction of preformed imines and imine derivatives and the reduction of imines formed in situ in reductive amination reactions. Both kinds of reductions are highlighted with emphasis on their scope and applications. Particular emphasis has been given to reductive amination with NaBH(OAc)3, the use of chiral N-sulfinyl imines in enantioselective synthesis of amines, and the stereoselective reductions of N-phosphinyl imines. Several alternative and emerging procedures for reductive amination and reduction of imines are also highlighted.