Method for preparing a compound of general formula: where: - R 1 is selected from the group formed by -Ar-CO-Z; a hydrogen atom (-H); - L-H; -G and -L-G; with Ar, Z, L and G being defined below; - R 3, R 4, R 6 and R 7 are each independently selected from the group formed by -(Ar) m -CO-Z; a hydrogen atom (-H); -L-H; -G and -L-G; where m is 0 or 1; on the understanding that only one of the substituents R 1, R 3, R 4, R 6 and R 7 is -Ar-CO-Z or -(Ar) m -CO-Z; - R 2 and R 5, the same or different, are each independently selected from the group formed by a hydrogen atom (-H); -L-H; -G and -L-G; with L and G being defined below; - S 1 and S 2 are hydrophilic groups, the same or different, of formula -C≡C-L'-A; with L' and A being defined below; - Ar is selected from among a C 5 -C 14 arylene or heteroarylene on which the group -CO-Z is at ortho, meta or para position preferably para; - Z is selected from among the groups -OH, -O-succinimide, -O-maleimide, - N-glycine, -N-lysine, -Y-L"-NH 2, -Y-L"-COOH, -Y-L"-SH where Y is selected from among the atoms of N and O and L" is defined below; - L and L" are each independently selected from among a single bond; a saturated, optionally branched C 1 -C 10 carbon chain, preferably C 1 -C 6; a C 6 -C 16 arylene on which the groups -H or -G for L and -NH 2, -COOH or -SH for L" are at ortho, meta or para position preferably para; a C 2 -C 4 alkenylene; C 2 -C 4 alkynylene; straight-chain or branched C 1 -C 20 carbon chain interrupted by 1 to 10 oxygen atoms; a saturated, straight-chain or branched C 1 -C 20 carbon chain interrupted by one to four -CO-NH- amide functions, a nucleotide segment and/or sugar segment; - G is selected from the group formed by the succinimidyl ester, sulfosuccinimidyl ester, isothiocyanate, isocyanate, iodoacetamide, maleimide, halosulfonyls, phosphoramidites, C 2 -C 5 alkylimidates, C 6 -C 10 arylimidates, halogeno-acids preferably chloroacids and bromoacids, hydrazines substituted by a C 1 -C 4 alkyl, hydroxylamines substituted by a C 1 -C 4 alkyl, carbodiimides and perfluorophenols; - L' is selected from among a single bond; a C 1 -C 10 alkenylene or a saturated, straight-chain or branched C 1 -C 20 carbon chain interrupted by 1 to 10 oxygen atoms; - A is a group selected from among a C 1 -C 4 alkyl, preferably methyl; a phosphate group or sulfonate group, said method being characterized in that it comprises the conversion of the synthesis intermediate P-(Ar) m -Q to a compound of general formula by reaction with a carbon source in the presence of a nucleophile selected from among water, an alcohol, an amine or thiol and a palladium catalyst; said intermediate is such that P is a group having identical structure with the compound of general formula to be prepared with the exception of the radical R 1 or R 3 or R 4 or R 6 or R 7 according to which one is the -Ar-CO-Z group for R 1 or -(Ar) m -CO-Z group for R 3 or R 4 or R 6 or R 7, said radical being a bond attached to -(Ar) m -Q; Ar is such as defined for formula, m is 0 or 1, on the understanding that m is 1 if R 1 is the carbonyl function -Ar-CO-Z, and Q is selected from among a halogen atom; an -O-triflate; O-tosylate or -O-mesylate. - R 1 is selected from the group formed by -Ar-CO-Z; a hydrogen atom (-H); - L-H; -G and -L-G; with Ar, Z, L and G being defined below; - R 3, R 4, R 6 and R 7 are each independently selected from the group formed by -(Ar) m -CO-Z; a hydrogen atom (-H); -L-H; -G and -L-G; where m is 0 or 1; on the understanding that only one of the substituents R 1, R 3, R 4, R 6 and R 7 is -Ar-CO-Z or -(Ar) m -CO-Z; - R 2 and R 5, the same or different, are each independently selected from the group formed by a hydrogen atom (-H); -L-H; -G and -L-G; with L and G being defined below; - S 1 and S 2 are hydrophilic groups, the same or different, of formula -C≡C-L'-A; with L' and A being defined below; - Ar is selected from among a C 5 -C 14 arylene or heteroarylene on which the group -CO-Z is at ortho, meta or para position preferably para; - Z is selected from among the groups -OH, -O-succinimide, -O-maleimide, - N-glycine, -N-lysine, -Y-L"-NH 2, -Y-L"-COOH, -Y-L"-SH where Y is selected from among the atoms of N and O and L" is defined below; - L and L" are each independently selected from among a single bond; a saturated, optionally branched C 1 -C 10 carbon chain, preferably C 1 -C 6; a C 6 -C 16 arylene on which the groups -H or -G for L and -NH 2, -COOH or -SH for L" are at ortho, meta or para position preferably para; a C 2 -C 4 alkenylene; C 2 -C 4 alkynylene; straight-chain or branched C 1 -C 20 carbon chain interrupted by 1 to 10 oxygen atoms; a saturated, straight-chain or branched C 1 -C 20 carbon chain interrupted by one to four -CO-NH- amide functions, a nucleotide segment and/or sugar segment; - G is selected from the group formed by the succinimidyl ester, sulfosuccinimidyl ester, isothiocyanate, isocyanate, iodoacetamide, maleimide, halosulfonyls, phosphoramidites, C 2 -C 5 alkylimidates, C 6 -C 10 arylimidates, halogeno-acids preferably chloroacids and bromoacids, hydrazines substituted by a C 1 -C 4 alkyl, hydroxylamines substituted by a C 1 -C 4 alkyl, carbodiimides and perfluorophenols; - L' is selected from among a single bond; a C 1 -C 10 alkenylene or a saturated, straight-chain or branched C 1 -C 20 carbon chain interrupted by 1 to 10 oxygen atoms; - A is a group selected from among a C 1 -C 4 alkyl, preferably methyl; a phosphate group or sulfonate group,