Structural Remodeling of Amines and Alcohols
Efforts in the Lipshultz Group are geared towards developing versatile platforms for structural remodeling of abundant amines and alcohols through designer radical reaction pathways. In particular, novel activation manifolds driven by photochemical excitation allow for rational manipulation of radical intermediates to achieve unconventional bond activations. Platforms for amine remodeling draw inspiration from Vitamin B6 (pyridoxal 5'-phosphate, "PLP"). In practice, optimized PLP-like aldehydes serve as activators to enable to desired amine remodeling pathways via (i) catalytic photodecarboxylation and (ii) radical amine migration, inspired by PLP-dependent decarboxylase and aminomutase enzymes, respectively. Platforms for alcohol remodeling take advantage of the photoactivity of titanium alkoxides via ligand-to-metal charge-transfer (LMCT) excitation. Through electronic tuning of the photoactive titanium species, excited state decay pathways can be rationally manipulated, enabling catalyst-controlled O-centered radical reactivity. Additionally, tuning of the Ti redox properties can enable reversible C–C bond activation for formal alcohol metathesis. Fundamental mechanistic studies, combined with density functional theory calculations, deliver deeper understanding of each mechanistic paradigm and provide prospects for further development.
