Several methods for the desulfurisation of Cys residues have been reported in the literature. These include photo-induced desulfurisation using a ruthenium PC, photo-desulfurisation in flow, accelerated desulfurisation using tetraethylborate (NaBEt4), desulfurative borylation , and the exploitation of phosphite and phosphine-dependent pathways . We attempted to adapt and explore two appropriate examples. However, both the use of NaBEt4 and a ruthenium photocatalyst failed to improve on our reported conditions (Figures S63 and S64-67).