A process for the preparation of a compound of formula wherein PG 1 is a nitrogen protecting group; R 0 is selected from the group consisting of hydrogen, C 1-4 alkyl and benzyl; R 6 is selected from the group consisting of hydrogen and C 1-6 alkyl; R 4 is aryl; wherein the aryl is optionally substituted with one to five substituents independently selected from the group consisting of C 1-6 alkyl, C 1-6 alkoxy, arylC 1-6 alkoxy, arylC 1-6 alkylcarbonyloxy, heteroarylC 1-6 alkylcarbonyloxy, heteroaryl, hydroxy, halogen, aminosulfonyl, formylamino, aminocarbonyl, C 1-6 alkylaminocarbonyl, di(C 1-6 alkyl)aminocarbonyl, heterocyclylcarbonyl, carboxy, and cyano; wherein the C 1-6 alkyl is optionally substituted with amino, C 1-6 alkylamino, or (C 1-6 alkyl) 2 amino; and wherein the aryl portion of arylC 1-6 alkylcarbonyloxy is optionally substituted with one to four substituents independently selected from the group consisting of C 1-6 alkyl, C 1-6 alkoxy, halogen, cyano, amino and hydroxy; and pharmaceutically acceptable enantiomers, pharmaceutically acceptable diastereomers, pharmaceutically acceptable racemates and pharmaceutically acceptable salt thereof; comprising reacting a compound of formula, wherein PG 1 is a nitrogen protecting group, with zinc; in the presence of a source of iodine; in a first organic solvent, or a mixture of organic solvents wherein the first organic solvent is non-reactive to the source iodine; to yield the corresponding compound of formula; reacting the compound of formula with a compound of formula, wherein LG 1 is a bromo group; in the presence of a palladium catalyst and phosphine ligand system; in a second organic solvent or a mixture of organic solvents; to yield the corresponding compound of formula. PG 1 is a nitrogen protecting group; R 0 is selected from the group consisting of hydrogen, C 1-4 alkyl and benzyl; R 6 is selected from the group consisting of hydrogen and C 1-6 alkyl; R 4 is aryl; wherein the aryl is optionally substituted with one to five substituents independently selected from the group consisting of C 1-6 alkyl, C 1-6 alkoxy, arylC 1-6 alkoxy, arylC 1-6 alkylcarbonyloxy, heteroarylC 1-6 alkylcarbonyloxy, heteroaryl, hydroxy, halogen, aminosulfonyl, formylamino, aminocarbonyl, C 1-6 alkylaminocarbonyl, di(C 1-6 alkyl)aminocarbonyl, heterocyclylcarbonyl, carboxy, and cyano; wherein the C 1-6 alkyl is optionally substituted with amino, C 1-6 alkylamino, or (C 1-6 alkyl) 2 amino; and wherein the aryl portion of arylC 1-6 alkylcarbonyloxy is optionally substituted with one to four substituents independently selected from the group consisting of C 1-6 alkyl, C 1-6 alkoxy, halogen, cyano, amino and hydroxy; and pharmaceutically acceptable enantiomers, pharmaceutically acceptable diastereomers, pharmaceutically acceptable racemates and pharmaceutically acceptable salt thereof; comprising reacting a compound of formula, wherein PG 1 is a nitrogen protecting group, with zinc; in the presence of a source of iodine; in a first organic solvent, or a mixture of organic solvents wherein the first organic solvent is non-reactive to the source iodine; to yield the corresponding compound of formula; reacting the compound of formula with a compound of formula, wherein LG 1 is a bromo group; in the presence of a palladium catalyst and phosphine ligand system; in a second organic solvent or a mixture of organic solvents; to yield the corresponding compound of formula.