New highly enantioselective process for the preparation of enantiomerically pure cyclopentane-beta-amino acids and cyclopentene-beta-amino acids

摘要

Prepn. of enantiomerically pure cyclopentane- or cyclopentene- beta -aminoacids of formula (I) comprises:(a) converting a meso-cyclopentane- or cyclopentene dicarboxylic anhydride of formula (II) into an enantiomerically pure monoester of formula (IVa) via enantiomerically pure salt of formula (IV), by asymmetric alcoholysis with an alcohol of formula (III) in a solvent in presence of an equimolar amt. of a chiral amine base in pure enantiomer form;(b) activating the free carboxy function then reacting with liq. ammonia to give the enantiomerically pure amide of formula (V);(c) cleaving the ester residue R15 in an inert solvent in presence of a nucleophilic auxiliary, by enzymatic methods or in presence of a palladium catalyst to give the acid or salt of formula (VI);(d) carrying out Hoffmann rearrangement with alkali(ne earth) metal hypochlorite in aq. alkali(ne earth) metal hydroxide soln.;(e) blocking the free amino gp. in soln. using a conventional amino-protecting gp., isolating the protected cpds. and cleaving the protecting gp. to give the pure enantiomer of (I). A,L = H;D, E = H, halo, OH or 1-8C alkyl,etc.; or D+E = =CR6R7, =N-OH, =O or =S; or A+D or E+L = additional bond;R6, R7 = H, halo, 1-8C alkyl, 1-8C alkoxy,etc.; R2 = H, amino-protecting gp., 1-8C alkyl (opt. substd. by 1 or 2 of OH, CHO up to 6C acyl, phenyl and benzoyl, where phenyl and benzoyl are themselves opt. substd. by 1 or 2 of halo, NO2, CN and 1-6C alkyl),etc.;R3 =H or 1-8C alkyl (opt. substd. by phenyl); or R2+R3 = =CHR14;R14 = H or 1-8C alkyl (opt. substd. by halo, OH,etc.;T = O, S or NH; R1 = H, 1-8C alkyl (opt. substd. by 1-3 of OH, halo,etc.), phenyl (opt. substd. by 1-3 of OH, halo, NO2,etc.);or if T = e.g. NH, R15 = 2-5C alkyl or 2-5C alkenyl (opt. substd. by CN, SiMe3, Ph or CCl3);V = chiral amine base;X = H, alkali metal or alkaline earth metal. Enantiomerically pure cpds. (IV), (IVa) and (V) are new.