Protected beta-homolysine of high enantiomeric purity (ee > 99.5%) is prepared utilizing the stereoselective conjugate addition of lithiated (S)-(alpha-methylbenzyl)benzylamide to (E)-7-(tosyloxy)hept-2-enoic acid tert-butyl ester, followed by subsequent ammonia substitution, Boc protection and removal of the auxiliary. (C) 2000 Elsevier Science Ltd. All rights reserved.