The present invention relates to a cycloaddition process comprising the step of reacting a halogenated aliphatic 1,3-dipole compound with a (hetero)cycloalkyne according to Formula (1): Preferably, the (hetero)cycloalkyne according to Formula (1) is a (hetero)cyclooctyne. The invention also relates to the cycloaddition products obtainable by the process according to the invention. The invention further relates to halogenated aliphatic 1,3-dipole compounds, in particular to halogenated aliphatic 1,3-dipole compounds comprising N-acetylgalactosamine-UDP (GalNAc-UDP), and to halogenated 1,3-dipole compounds comprising (peracylated) N-acetylglucosamine (GlcNAc), N-acetylgalactosamine (GalNAc), N-acetylmannosamine (ManNAc) and N-acetyl neuraminic acid (NeuNAc).