P-chirogenic compounds have played important roles in organic chemistry, as ligands in metal catalysis, as supramolecules and as organic catalysts. As part of our studies to develop a new method to prepare such species, we came to interest in developing catalytic P-oxygenation. One of the focuses in our group is to expand the scope of catalytic reactions using cofactor flavin derivatives. In analogy with known heteroatom oxygenation of flavin-dependent oxidases, P-oxygenation of phosphine 1 in the presence of flavin derivatives were tested. Although 1 can be slowly oxidized under air without catalyst (autoxidation), the oxidation was enhanced with flavin derivatives. After much screening, we found a unique effect of amine additive that shuts down this autoxidation while enhances flavin-promoted oxygenation. With optimization of reaction conditions, the best conditions were found to be: Fl-Bn (0.1 equiv.) and Et3N (1.0 equiv.), in 2,2,2-trifluoroethanol, at room temperature. Under these conditions, the reaction was completed within half an hour, or within 24h with 1 mol% of the catalyst. Our working mechanism based on spectroscopic studies and a series of control experiments, as well as scope and limitation of the reaction will also be presented.

Catalytic P-oxygenation promoted by cofactor flavin derivative

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

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