REDUCTION OF IMINES VIA TITANIUM-CATALYZED HYDROMAGNESATION

We have recently discovered that imines can be reduced to amines via a titanium catalyzed hydromagnesation reaction. These reactions employ n-BuMgCl (1.2 eq) as the stoichiometric reducing agent and Cp2TiCl2 (3 -5 mol%) as a catalyst. Reactions are run under nitrogen at ambient te mperature and pressure. For most aldimine and cyclic ketimine substrat es amine products are obtained in yields ranging from 69-94%. The reac tion is not tolerant of bulky nitrogen substituents or primary enoliza ble protons on the imine substrate. (C) 1997 Elsevier Science Ltd.