Disclosed are novel conjugates and processes for the preparation thereof. A process for the preparation of alkene-or alkyne-phosohonothiolates and -phosphonates comprises the step of: reacting a compound of formula (I) with a thiol-containing molecule of formula (II) wherein represents an amino acid, a peptide, a protein, an antibody, a nucleotide, an oligonucleotide, a saccharide, a polysaccharide, a polymer, an optionally substituted C
