DIASTEREOSELECTIVE PROCESS FOR PREPARING N-SUBSTITUTED AMINO ACIDS AND DERIVATIVES

摘要

A process for preparing an (S, S) or (R, R) diastereoisomer of formula (X) or salts, esters or amides thereof, wherein R?3 and R4¿ independently represent hydrogen, alkyl, aryl or aryl substituted with halogen, alkyl, nitro or alkoxy, and n and m independently represent integers from one to six, comprising combining a cyanide compound of the formula: M1C=N, wherein M1 is hydrogen, trimethylsilyl or a metal, with an optional proton source, a solvent and a Lewis acid of the formula: M2X4, AlCl3 or BF3, wherein M2 is Sn or Ti and X represents chloro, bromo, fluoro or iodo, with an α-amino acid compound or salts or esters thereof, followed by addition of an acyl or acetal compound to give the diastereoisomer of formula (X).