Staudinger ligation reagent for the conjugation of amine and azide containing compounds or biomolecules.
The amine functionalized molecule first reacts with the phosphine through the activated pentafluorophenyl ester.The azide-molecule is then reacted with the newly labeled phosphine to form the iminophosphorane, and the aza-ylide is subsequently captured by the methyl ester to yield the covalent conjugated product.