Rational synthesis of all the four stereoisomers of 3-(trans-2-aminocyclopropyl)alanine

All the four stereoisomers of 3-(trans-2-aminocyclopropyl)alanine – a key constituent of the potential antitumor agent belactosin A – were prepared by simple catalytic hydrogenation of (2S,1'S,2'S)-, (2S,1’R,2’R)-, (2R,1’R,2’R)-, and (2R,1'S,2'S)-3-(trans-2-nitrocyclopropyl) alanines in 95, 93, 91 and 92% yields, respectively.