A Practical Diastereoselective Synthesis of (−)‐Bestatin

Abstract

Diastereoselective addition of nitromethane to Boc‐D‐Phe‐H in the presence of sodium hydride in diethyl ether/hexane containing 15‐crown‐5 and subsequent N,O‐protection with 2,2‐dimethoxypropane gave trans‐oxazolidine in a diastereomeric ratio of >16:1. The oxazolidine was easily separated by column chromatography, which after Nef reaction was coupled to H‐Leu‐OtBu. The 8‐step synthesis afforded (−)‐bestatin in an overall yield of 24.7% after deprotection and ion exchange.

DOI: 10.1002/psc.3067

Authors from Peptides International