Title: Designing, Understanding, and Manipulating Radical Reaction Pathways Driven by Light
Abstract: Efforts in the Lipshultz Group are largely geared towards developing versatile platforms for synthetic transformations, leveraging radical reaction pathways driven by light. Among these platforms are (i) titanium ligand-to-metal charge-transfer (LMCT) photocatalysis, (ii) Vit B6-inspired Photo-Decarboxylase catalysis, and (iii) Vit B6-dependent aminomutase-inspired amino acid homologation. Each of these reaction classes leverages unique photochemical and/or radical key steps which provide opportunity for manipulation and control through fundamental understanding. First, electronic tuning of photoactive titanium catalysts allows for rational manipulation of photochemistry, manifesting in controlled photocatalysis for C–C and C–H bond functionalization. Tuning of the redox properties can further enable reversible C–C bond activation for formal alcohol metathesis. Second, taking inspiration from Dunathan’s stereoelectronic hypothesis for Vit B6-dependent enzymatic reactivity, Photo-Decarboxylase catalysis is realized through catalyst-templated hyperconjugative charge-transfer, delivering access to decarboxylated diradical species which engage in regiospecific bond construction. Finally, α-to-β amino acid homologative transmutation can be achieved through a highly polarized biomimetic 3-exo-trig radical cascade. Fundamental mechanistic studies, combined with density functional theory calculations, deliver deeper understanding of each mechanistic paradigm and provide prospects for further development.
Bio: Jeff was born in New York City and raised in North Jersey. In 2013, he received an A.B. in Chemistry from Harvard College, where he worked in the lab of Prof. Andrew Myers, supporting efforts towards unnatural analogue synthesis of cortistatin and trioxacarcin natural products. Jeff returned to New Jersey to pursue graduate studies with Prof. David MacMillan at Princeton University, where he worked on reaction development using metallaphotoredox catalysis and total synthesis of oligomeric polypyrroloindoline natural products. After receiving his Ph.D. in 2018, Jeff once again shipped up to Boston for a postdoctoral stay with Prof. Alexander Radosevich at MIT, developing new reaction methods employing organophosphorus catalysis. Jeff began his independent career in the Department of Chemistry at Stony Brook University as an Assistant Professor in Summer 2022. Outside of lab, Jeff enjoys spending time with his wife Alyssa and son Jonah, listening to Bruce Springsteen, and rooting for his favorite teams – the Yankees, Devils, and Giants.
Host: Zach Wickens