Periodic Reporting for period 2 - ElectroNick (The Combination of Electrochemistry and Nickel Catalysis: New Bond-Forming Reactions on a Sustainable Platform)
Período documentado: 2020-05-01 hasta 2021-04-30
To this end, ElectroNick aims at establishing a suite of new electrocatalytic carbon–carbon bond formation reactions using nickel complexes as efficient catalysts for synthesis. Reactive intermediates can be forged within the reaction mixture, limiting the waste of metals such as zinc and cobalt. Not only will these reactions improve sustainability in organic synthesis, they will provide the possibility of designing the synthesis of new carbon–carbon bonds with high efficiency and selectivity. However, in order to design these new catalytic systems, it is important to build a deep understanding of the multiple steps within each catalytic cycle, and how subtle changes in the metal complex or substrates that form the new carbon–carbon bond affect overall reactivity. ElectroNick has utilized cutting-edge techniques in electroanalysis and ‘big data’ science to understand these intricate effects, and employed the knowledge gained through these processes in developing new reactions for carbon–carbon and carbon–heteroatom bond formation.
With that in hand, we used the same toolkit to understand how the Co(I) would react productively with organic molecules, developing understanding on how, of many possibilities, the Co(I) would add into a carbon–bromine bond (oxidative addition). This strategy of combining electroanalytical techniques with statistical modeling to understand these processes represents a significant advance in building methods to interrogate reactivity, and we have expanded its use to investigating reactivity with alternative substrates and nickel complexes. Finally, the statisical modeling techniques were utilized to understand intricate interactions which drive selectivity in a new palladium catalyzed transformation, forging new carbon–nitrogen and carbon–oxygen bonds towards pharmaceutical targets.
In the outgoing phase of ElectroNick, the project developed new tools combining electroanalytical techniques with statistical modeling to interrogate reaction mechanisms. Our results uncovered how Co(I) complexes add into a carbon–bromine bond through a specific oxidative addition mechanism. In an extension to that study, we have investigated how Co(I) complexes with different ligand scaffolds can change the mechanism of activation of the substrate to alternative processes, including the transfer of an electron into the carbon–bromine bond (concerted dissociative electron transfer). Additionally, we expand our studies beyond the confines of Co(I) complexes to include other transition metals. In doing so, we have formulated a platform to globally understand and predict reactivity between metals and organic molecules that can be used to design new reactions for pharmaceutical and agrochemical synthesis.
With knowledge of how these reactions occur mechanistically, we have sought to develop new carbon–carbon and carbon–heteroatom bond forming reactions using the combination of electrochemistry and nickel catalysis. The ElectroNick project has realized early studies indicating that the functionalization of simple carbon–hydrogen bonds can be achieved by these techniques, and work to expand these principles to transformative new reactions remains ongoing within the research groups.
Altogther, ElectroNick has thus far afforded four open access publications in scientific journals, was presented at two interantional conferences and eight invited seminars, and been disseminated to the wider public through social media, video clips and outreach activities.