The antifungal antibiotic (-)-(1R,2S)-2-aminocyclopentane-1-carboxylic
acid (cispentacin) 4 has been prepared via the highly stereoselective
conjugate addition reaction of lithium (S)-(alpha-methylbenzyl)benzyl
amide (S)-2 to tert-butyl 1-cyclopentene-1-carboxylate 1.