Photo-induced radical-ionic bis-functional-group transfer reactions from single, readily available oxime-based surrogates containing a sulfinyl tether

• Applicant: Professor Dr. Martin Oestreich
• Subject Area: Organic Molecular Chemistry - Synthesis and Characterisation
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 520479209

This project aims at the development of a new family of reagents that, under photochemical irradiation, enables the transfer of two molecular fragments from one surrogate onto C–C multiple bonds. The reagent design is guided by accessibility (simple synthetic operations followed by straightforward purification procedures) and scalability (multigram scale) as well as programmable modularity. These boundary conditions are met by a novel oxime-based platform containing a sulfinyl group as a tether. Unlike photochemical energy-transfer catalysis with other oxime-derived systems, the photoredox-catalyzed activation of the targeted reagents involves single-electron transfer, thereby leading to their fragmentation into a radical and an anion along with sulfur dioxide. The radical would add to the unsaturated C–C bond followed by radical–polar crossover through oxidative quenching by the photocatalyst. The resulting cationic intermediate is then captured by the previously released anion. The viability of this strategy has already been shown by us for a dihalogenation of alkenes, allenes, and alkynes using an easy-to-make dihalogen surrogate. By employing more elaborate sulfinyl-tethered, oxime-based reagents, we plan to accomplish the transfer of cyanogen halides and silyl chlorides as well as, with C–C bond formation, chlorofluorocarbons and acyl chloride to alkenes and other multiple bonds.

• DFG Programme: Research Grants