Proton-coupled electron transfers (PCETs) are unconventional redox processes in which an electron and proton are exchanged together in a concerted elementary step. While these mechanisms are recognized to play a central a role in biological redox catalysis and inorganic solar energy conversion technologies, their applications in synthetic organic chemistry remain largely unexplored. My lecture will highlight recent work from my group that explores the use concerted PCET activation to address unmet synthetic challenges. Central to this work is the idea that concerted PCET can serve as a general mechanism for homolytic bond activation that is complementary to and potentially broader in scope than conventional hydrogen atom transfer (HAT) chemistry. A simple energetic model will be presented that enables us to rationally design catalyst systems competent to oxidatively break very strong sigma bonds (BDFEs ~ 100 kcal/mol) or to reductively form extremely weak bonds (BDFEs ~ 20 kcal/mol) through PCET activation of pi systems. Accordingly these methods enable us to generate a wide variety of synthetically valuable radical intermediates directly from their native functional group precursors under unusually mild catalytic conditions. Hydrogen-bonding based approaches for controlling enantioselectivity in the subsequent reactions of the free radical intermediates formed in these PCET events will also be presented.

Proton-coupled electron transfer in organic synthesis and asymmetric catalysis

249th National Meeting (2015)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.