The work carried out during the MSC Action can be divided into two parts:
(1) Electrochemistry-enabled reversible shuttle dihalogenation reactions (published in Science 2021, 371, 507–514)
The researcher has successfully developed an electrochemistry-enabled shuttle (e-shuttle) process to transfer the Cl2 and Br2 entities between 1,2-dihalides and alkenes reversibly, similar to an airport shuttle bus transports passengers back and forth between two terminals. Driven by renewable and sustainable electricity, this enabling method replaces the corrosive and toxic elemental chlorine and bromine in synthesizing vicinal dichlorides and dibromides, enhancing the safety of chemical processes. Meanwhile, it also renders the synthesis of fine chemicals from the remediation of the Lindane contaminated soils without any pre-treatment. When Lindane was subjected to our standard e-shuttle conditions with alkenes as acceptors, Lindane successfully transferred its six chlorine atoms to the acceptor alkene to form benzene, the fully dechlorinated byproduct of Lindane, alongside a synthetically valuable dichloride product, through three successive retro-dichlorination events. We believe that this research work opens up new opportunities to replace the traditional linear "take-make-dispose" approach with a circular process in handling end-of-life chemical pollutants, contributing to protecting the environment and securing a sustainable future.
Since its publication, this research work has attracted media coverage regarding its exceptional novelty, sustainability, and promising application in environmental protection. The positive feedback came not only from the chemistry community but also from the general public media, such as Frankfurter Allgemeine, Nat. Catal., C&EN News, ChemistryViews, ETH news, JGU news, and Chem Europe.
(2) Electrochemistry-enabled shuttle hetero-difunctionalization reactions (manuscript submitted for publication)
The researcher developed an electrochemistry-enabled shuttle strategy to transfer two distinct functional groups, a sulfide and a halide, between β-halosulfide and alkynes with excellent chemo-, regio-, and stereoselectivity, unlocking a rare example of shuttle hetero-difunctionalization reaction. The paired electrolysis process, which is considered a holy grail by the electrochemistry community, was successfully employed to deconstruct and reconstruct two different inert chemical bonds sequentially. More importantly, the selective anodic oxidation of one anion over the other, by taking advantage of differences in redox potentials, serves as the critical design to achieve unprecedented chemoselectivity. This easily scalable methodology enables the construction of a myriad of densely functionalized β-halo alkenyl sulfides in unprecedented chemo-, regio-, and stereoselectivity using benign surrogates, e.g. 2-bromoethyl sulfide, avoiding the handling of corrosive and oxidative RS–Br reagents. Moreover, the researcher also successfully performed the defunctionalization reaction of β-bromosulfide compounds to their corresponding alkenes without releasing the toxic sulfenyl bromide reagents, taking advantage of the reversibility of the shuttle process.
