A method for the synthesis of a compound of general formula I wherein Hal is F, Cl, Br, or I; R is H or an optionally substituted C 1 -C 4 alkyl group, an optionally substituted C 1 -C 4 alkoxy group, an optionally substituted aryl group, an optionally substituted heteroaryl group, an optionally substituted C 1 -C 4 alkyl carboxy C 1 -C 4 alkyl group, Hal, CN, an optionally substituted C 1 -C 4 alkylsulfonyl group, an optionally substituted arylsulfonyl group, or an NR z group as defined below; R 1 is H or a C 1 -C 4 alkyl group or a C 1 -C 4 alkoxy group; X 1 is a protecting group; L is a connecting group for covalent linkage whereby L has the general structure Z-Y-Z'; Z and Z' are independently from one another selected from C = O, OC = O, SO 2, NRz, NR 2 C = O, C = O NR z, wherein each R z is independently from one another selected from H, optionally substituted C 1 -C 4 alkyl group or optionally substituted C 1 -C 4 acyl; wherein Y is an optionally substituted C 1- C 10 alkyl group, a group of structure VIII: wherein o and p are independently from one another selected from an interger of 1 to 20, whereby o and p may be the same integer or a different integer, X 3 is i) N, S or O, or ii) an aryl group or a heteroarylgroup, wherein [C(R a) 2] O and [C(R a) 2] p are present in the metaposition of said aryl group or said heteroaryl group, each R A is independently from one another selected from H or an optionally substituted C 1 -C 4 alkyl group or an optionally substituted C 1 -C 4 acyl group; comprising the step of reacting a compound of formula II wherein R, R 1, and Hal are defined as above and X 2 is a protecting group which may be identical or different to X 1 above, with a deprotecting agent for deprotecting the X 2 group from the compound of formula II; subsequently, reacting the deprotected compound of formula II with a compound of formula III wherein the substituents Hal, R 1, X 1 and R are defined as above and L is a connecting group as defined above, R 3 is selected from Hal, in particular, Cl and Br, and OH in the presence of a coupling agent and a base to obtain a compound of formula I; wherein the compound of formula III is obtained by reacting a compound of IV wherein X 1, X 4, R, R 1 and Hal are defined as above, X 4 is a protecting group as defined for X 1 and X 1 and X 4 are different from each other, with a compound of general formula VII VII R 5 -L-R 6 with L being Z - Y - Z' and wherein Z, Y and Z' are defined as above and R 5 and R 6 are independently from one another selected from a halogenor an OH group. whereby in a first step the compound of formula IV is deprotected at the X 4 group by reacting the same with a deprotecting agent and, subsequently, the deprotected compound of formula IV is reacted with the compound of formula VII in the presence of a base to obtain the compound of formula III. R is H or an optionally substituted C 1 -C 4 alkyl group, an optionally substituted C 1 -C 4 alkoxy group, an optionally substituted aryl group, an optionally substituted heteroaryl group, an optionally substituted C 1 -C 4 alkyl carboxy C 1 -C 4 alkyl group, Hal, CN, an optionally substituted C 1 -C 4 alkylsulfonyl group, an optionally substituted arylsulfonyl group, or an NR z group as defined below; R 1 is H or a C 1 -C 4 alkyl group or a C 1 -C 4 alkoxy group; X 1 is a protecting group; L is a connecting group for covalent linkage whereby L has the general structure Z-Y-Z'; Z and Z' are independently from one another selected from C = O, OC = O, SO 2, NRz, NR 2 C = O, C = O NR z, wherein each R z is independently from one another selected from H, optionally substituted C 1 -C 4 alkyl group or optionally substituted C 1 -C 4 acyl; wherein Y is an optionally substituted C 1- C 10 alkyl group, a group of structure VIII: wherein o and p are independently from one another selected from an interger of 1 to 20, whereby o and p may be the same integer or a different integer, X 3 is i) N, S or O, or ii) an aryl group or a heteroarylgroup, wherein [C(R a) 2] O and [C(R a) 2] p are present in the metaposition of said aryl group or said heteroaryl group, each R A is independently from one another selected from H or an optionally substituted C 1 -C 4 alkyl group or an optionally substituted C 1 -C 4 acyl group; comprising the step of reacting a compound of formula II wherein R, R 1, and Hal are defined as above and X 2 is a protecting group which may be identical or different to X 1 above, with a deprotecting agent for deprotecting the X 2 group from the compound of formula II; subsequently, reacting the deprotected compound of formula II with a compound of formula III wherein the substituents Hal, R 1, X 1 and R are defined as above and L is a connecting group as defined above, R 3 is selected from Hal, in particular, Cl and Br, and OH in the presence of a coupling agent and a base to obtain a compound of formula I; wherein the compound of formula III is obtained by reacting a compound of IV wherein X 1, X 4, R, R 1 and Hal are defined as above, X 4 is a protecting group as defined for X 1 and X 1 and X 4 are different from each other, with a compound of general formula VII VII R 5 -L-R 6 with L being Z - Y - Z' and wherein Z, Y and Z' are defined as above and R 5 and R 6 are independently from one another selected from a halogenor an OH group. whereby in a first step the compound of formula IV is deprotected at the X 4 group by reacting the same with a deprotecting agent and, subsequently, the deprotected compound of formula IV is reacted with the compound of formula VII in the presence of a base to obtain the compound of formula III.