A process for the preparation of an intermediate of formula I wherein the stereogenic center marked with an * is either in - or -configuration at marked center, or it is in racemic form, and wherein R 4 and R 5 are identical or different, and are independently selected from (i) hydrogen; (ii) alkyl residues optionally chiral, having from 1 to 12 carbon atoms, wherein the alkyl residues are optionally aryl and/or aryloxy substituted; (iii) alkyloxy residues optionally chiral, having from 1 to 12 carbon atoms, wherein the alkyloxy residues are optionally aryl substituted; (iv) aryl residues optionally chiral, having from 6 to 24 carbon atoms, wherein the aryl residues are optionally alkyl and/or alkyloxy substituted; (v) aryloxy residues optionally chiral, having from 6 to 24 carbon atoms, wherein the aryloxy residues are optionally alkyl substituted; (vi) benzyl; (vii) alkaloyl residues optionally chiral, having from 2 to 13 carbon atoms, wherein the alkaloyl residues are optionally aryl substituted; (viii) aroyl residues optionally chiral, having from 7 to 25 carbon atoms, wherein the aroyl residues are optionally alkyl substituted; and (ix) alkoxycarbonyl residues optionally chiral, having from 2 to 13 carbon atoms; (x) aryloxycarbonyl residues optionally chiral, having from 7 to 25 carbon atoms; and (xi) tosyl; wherein R 3 is selected from alkyl residues having from 1 to 6 carbon atoms; the process comprising the steps of: (a) providing an intermediate of formula II, (b) reacting the intermediate of formula II with a borating agent in a suitable solvent to obtain an intermediate of formula III, wherein the stereogenic center marked with an * is either in - or -configuration at marked center, or it is in racemic form, and wherein R 1 and R 2 are identical or different, and are selected from (i) alkyl or alkoxy residues, each having from 1 to 12 carbon atoms, wherein each alkyl or alkoxy residue is optionally aryl substituted, (ii) aryl or aryloxy residues, each having from 6 to 14 carbon atoms, wherein each aryl or aryloxy residue is optionally alkyl substituted; (iii) halides; and (iv) wherein R 1 and R 2 optionally form a chiral or non-chiral 5 to 10 membered mono or bicyclic ring, wherein the ring is optionally substituted at least one position with an alkyl residue having from 1 to 12 carbon atoms and/or an aryl residue having from 6 to 14 carbon atoms, and wherein R 1 and R 2 optionally form an O-benzenedioxy residue; and wherein R 3 is same as above; (c) converting the intermediate of formula III to the intermediate of formula I. (i) hydrogen; (ii) alkyl residues optionally chiral, having from 1 to 12 carbon atoms, wherein the alkyl residues are optionally aryl and/or aryloxy substituted; (iii) alkyloxy residues optionally chiral, having from 1 to 12 carbon atoms, wherein the alkyloxy residues are optionally aryl substituted; (iv) aryl residues optionally chiral, having from 6 to 24 carbon atoms, wherein the aryl residues are optionally alkyl and/or alkyloxy substituted; (v) aryloxy residues optionally chiral, having from 6 to 24 carbon atoms, wherein the aryloxy residues are optionally alkyl substituted; (vi) benzyl; (vii) alkaloyl residues optionally chiral, having from 2 to 13 carbon atoms, wherein the alkaloyl residues are optionally aryl substituted; (viii) aroyl residues optionally chiral, having from 7 to 25 carbon atoms, wherein the aroyl residues are optionally alkyl substituted; and (ix) alkoxycarbonyl residues optionally chiral, having from 2 to 13 carbon atoms; (x) aryloxycarbonyl residues optionally chiral, having from 7 to 25 carbon atoms; and (xi) tosyl; (a) providing an intermediate of formula II, (b) reacting the intermediate of formula II with a borating agent in a suitable solvent to obtain an intermediate of formula III, wherein the stereogenic center marked with an * is either in - or -configuration at marked center, or it is in racemic form, and wherein R 1 and R 2 are identical or different, and are selected from (i) alkyl or alkoxy residues, each having from 1 to 12 carbon atoms, wherein each alkyl or alkoxy residue is optionally aryl substituted, (ii) aryl or aryloxy residues, each having from 6 to 14 carbon atoms, wherein each aryl or aryloxy residue is optionally alkyl substituted; (iii) halides; and (iv) wherein R 1 and R 2 optionally form a chiral or non-chiral 5 to 10 membered mono or bicyclic ring, wherein the ring is optionally substituted at least one position with an alkyl residue having from 1 to 12 carbon atoms and/or an aryl residue having from 6 to 14 carbon atoms, and wherein R 1 and R 2 optionally form an O-benzenedioxy residue; and wherein R 3 is same as above; (i) alkyl or alkoxy residues, each having from 1 to 12 carbon atoms, wherein each alkyl or alkoxy residue is optionally aryl substituted, (ii) aryl or aryloxy residues, each having from 6 to 14 carbon atoms, wherein each aryl or aryloxy residue is optionally alkyl substituted; (iii) halides; and (iv) wherein R 1 and R 2 optionally form a chiral or non-chiral 5 to 10 membered mono or bicyclic ring, wherein the ring is optionally substituted at least one position with an alkyl residue having from 1 to 12 carbon atoms and/or an aryl residue having from 6 to 14 carbon atoms, and wherein R 1 and R 2 optionally form an O-benzenedioxy residue; (c) converting the intermediate of formula III to the intermediate of formula I.