Asymmetric synthesis of 2,3-methanoleucine stereoisomers from common intermediates

2,3-Methanoamino acids are useful probes for studying the bioactive conform ation of peptides and for investigating the effect of local conformational constraints on the activity of peptidomimetics. We synthesized all four ste reoisomers of Cbz-protected 2,3-methanoleucine for incorporation into pepti domimetic inhibitors of calpain. While the synthesis of 2,3-methanoamino ac ids has been previously reported, our procedure offers a versatile route in which the pair of diastereomers of each geometric isomer was synthesized f rom a common intermediate. (C) 2000 Wiley-Liss, Inc.