| Abstract: | More effective use of optical resolution processes can be obtained by increasing the overall yields after development of methods for inversion of the chiral centre of the unwanted isomer. The configuration of some optically active amines can be inverted in a three-step synthesis via the N,N-ditosylimides and a subsequent nucleophilic substitution by the azide ion. The azide product is reduced by hydrogenolysis. Low stereoselectivity caused by racemization to some extent was at first observed for the inversion of the benzylic substrate, (S)-α-methylbenzylamine ( 5a ). However, modified reaction conditions allowed increased stereoselectivity, a more rapid and almost complete inversion of this substate as well. © 1994 Wiley-Liss, Inc. |
