An improved chemoenzymatic protocol for the synthesis of both enantiomers of trans-cyclopentane-1,2-diamine is described. The key part of the strategy relies on the synthesis and subsequent enzymaticresolution of its racemic precursor trans-N,N-diallylcyclopentane-1,2-diamine in which the primary amino group is masked as a tertiary diallylamine. Lipase B from Candida antarctica (CAL-B) catalyzes the