Facile synthesis and highly efficient resolution of a constrained cyclopropane analogue of phenylalanine

Enantiomerically pure (2R,3R)- and (2S,3S)-1-(N-tert-butoxycarbonyl)amino-2,3-diphenyl-1-cyclopropanecarboxylic acids have been prepared by HPLC resolution of a racemic precursor. The complete stereoselectivity of the cyclopropanation process, together with the high efficiency of the subsequent transformations and the chromatographic resolution, allowed the preparation of optically pure compounds on a multigram scale.