Diastereoselective addition of methyllithium and dimethylcuprate boron trifluoride to imines derived from (S)-1-phenylethylamine

The reactions of dimethylcuprate-boron trifluoride reagents with the imines derived from (S)-1-phenylethylamine afforded the secondary amines by addition to the Si face of the imines. (S,S)-bis(1-phenylethyl)amine and (S)-1-cyclohexylethanamine were prepared with high stereoselectivity, in the latter case by a two step sequence involving the final cleavage of the auxiliary. Methyllithium attacked mainly the Si face of the imines derived from 4-pyridine carboxaldehyde and 2-methoxybenzaldehyde, but the Re face of the imines derived Own 2-pyridine and 2-furan carboxaldehyde. Copyright (C) 1996 Published by Elsevier Science Ltd