Graduate Student Fatema Amin

"Scalable and selective electroreduction protocols in organic syntheses and chemical recycling"

Electrochemistry has the advantage of setting up a precise redox potential for an organic synthesis which allows avoiding complex organic substrates, superstoichiometric use of additives, and a myriad of steps in industrial scale-up operations. Traditional reduction methods, being in use for years in syntheses, have now been impugned for its requisite of hazardous condensation of ammonia (e.g., in the Birch reduction1), caution in the reaction setup with pyrophoric metal powders, multistep use of protecting groups due to low chemoselectivity (ketone-olefin coupling2), vigorous evolution of flue gases3, and highly basic conditions required for strong reductive cleavage (e.g., Si-Cl bonds4), among others. In this context, electroreductive surrogates appeared to be the best alternative and hence, found their way in the gamut of synthetic chemistry, materials chemistry5 and, needless to say, in electronics. Reported in this seminar are some recent advances from Song Lin’s group on radical silylation via electroreductive Si-Cl bond activation6, Sevov’s group on electroreductive deoxygenation of Triphenylphosphine Oxide7 and Baran’s group on single route electroreductive ketone-olefin coupling2.

References:

1. Peters, B. K. et al. Scalable and safe synthetic organic electroreduction inspired by Li-ion battery chemistry. Science (80-. ). 363, 838–845 (2019).
2. Hu, P. et al. Electroreductive Olefin–Ketone Coupling. J. Am. Chem. Soc. 142, 20979–20986 (2020).
3. Morodo, R., Bianchi, P. & Monbaliu, J. M. Continuous Flow Organophosphorus Chemistry. European J. Org. Chem. 2020, 5236–5277 (2020).
4. Weyenberg, D. R., Toporcer, L. H. & Bey, A. E. The Disilylation of Styrene and α-Methylstyrene. The Trapping of Short-Lived Intermediates from Alkali Metals and Aryl Olefins1. J. Org. Chem. 30, 4096–4101 (1965).
5. Yang, H. et al. Carbon dioxide electroreduction on single-atom nickel decorated carbon membranes with industry compatible current densities. Nat. Commun. 11, 1–8 (2020).
6. Lu, L., Siu, J. C., Lai, Y. & Lin, S. An Electroreductive Approach to Radical Silylation via the Activation of Strong Si–Cl Bond. J. Am. Chem. Soc. (2020).
7. Manabe, S., Wong, C. M. & Sevov, C. S. Direct and Scalable Electroreduction of Triphenylphosphine Oxide to Triphenylphosphine. J. Am. Chem. Soc. 142, 3024–3031 (2020).