DIASTEREOSELECTIVE PROCESS FOR PREPARING N-SUBSTITUTED AMINO ACIDS AND DERIVATIVES

摘要

A process for preparing an (S, S) or (R, R) diastereoisomer of the formula (X) or its salts, esters or amides, wherein R3 and R4 independently represent hydrogen, alkyl, aryl, or aryl substituted halogen , alkyl, nitro or alkoxy, and n as well as m independently represent whole numbers between 1 and 6, consisting in combining a cyanide compound of the formula M1C = N, in which M1 represents hydrogen trimethylesilyl or a metal, having a source optional protons, a solvent as well as a Lewis acid of the formula: M2X4, AlCl3 or BF3, in which M2 represents Sn or Ti and X represents chloro, bromo, fluoro or iodo, comprising an alpha-amino acid compound or its salts or esters, after which an acyl or acetal compound is added in order to obtain the diastereoisomer of formula (X).