Novel applications of Meerwein arylation reactions for the conjugation and labelling under biomimetic conditions

A promising concept for a targeted modification of peptides and proteins at cysteine side chains has been developed. The use of a linker molecule helps to circumvent the lack of adequate targets for Meerwein arylation. Further arylation of the targets with a variety of aryldiazonium tetrafluoroborates has been demonstrated as well. Especially the successful arylation with the fluoresceine-derived diazonium salt enables fluorescence labelling of peptides. This diazonium salt has been tested regarding its applicability for aryl radical generation under mild conditions. It showed promising results for its application in Meerwein arylation reactions with a product scope giving carbohydroxylation products in yields up to 74%.