Electrochemical sulfonylation of lysine residues in continuous flow microreactors.
Peptides are important molecules, ubiquitous in biological systems. Their relevance in the pharmaceutical sector is proven by the constant increase which the global market of peptide-based drugs is experiencing in the last years. As a consequence, several methods have been developed to modify peptides (e.g. condensation, cross-coupling, transition-metal catalysis, and photocatalysis), being lysine with its free amine one of the most preferred handles used by chemists to introduce a new moieties, e.g. cytotoxic drugs or fluorescent labels. Several transformations as alkylation, arylation, oxidation, acylation and condensation have been described for lysine. However, it would be very appealing to introduce selectively a sulfonyl group, which would result in the formation of a sulfonamide, a functionality which is widely employed in drugs. Although several oxidative sulfonylations are reported in the literature, their drawbacks motivate me to look for greener synthetic strategies. Electrosynthesis represents an advantageous alternative, which has been re-discovered in the last years also thanks to its employment in continuous-flow microreactors. With the support of this modern technology, it is possible to minimize the difficulties connected to older electrochemical processes (such as mass-transfer limitation, the need of a supporting electrolyte,and the difficult scale-up). ELECTROSULF aims at developing a novel sulfonylation of lysine by electrochemical means with the use of a flow microreactor. The reaction mechanism will be also properly studied.  My strong background in organic chemistry together with Prof. Timothy Noël’s expertise in flow processes and reaction miniaturization will guarantee the success of ELECTROSULF, whose achievement will have a great impact on the pharmaceutical sector, paving the path to a new approach for peptide modification.