Patent ID: 7326805

Claim:
A process for synthesizing, alone or in mixtures, the two isomers, at the OH function, of the a amino acids, or their derivatives, of the general formula B: in which the C—O bond of the carbon in position 4 symbolizes one or other of the III or IV isomers, or their mixtures, R 1 and R 2 represent: a hydrogen atom, or either R 1 or R 2 represents a hydrogen atom and the other substituent is a radical R 8 , an acyl group —COR a , or else a functional group —COOR a , —SO 2 R a or —N (R a ,R b ), with R a and R b , which are identical or different, being a linear or branched C1-C12 alkyl radical, which is optionally substituted, an aryl group having one or more aromatic and heterocycle rings comprising 5 to 8C, which is optionally substituted, or aralkyl, with the alkyl substituent and the awl group being as defined above, or R 1 and R 2 both represent a substituent as defined above, R 3 represents a hydrogen atom or R a , and R 4 has the meanings of R a , chamcterized in that it comprises: the isomerization of a compound of the formula I: in which R 1 , R 2 , R 9 , R 3 and R 4 are as defined above, so as to obtain a compound of the formula II: the reduction of its carbonyl function, which leads, depending on the catalytic system which is used and the compound of the formula I which is employed, to one of the isomers of the general formula III or VI or to their mixture of the formula B: with the substituents R a and R 1 to R 4 being as defined above.