Speaker
Shawn Wright
Speaker's Institution
Colorado State University
Date
6/6/22
Time
4:00pm
Location
Chemistry A101
Mixer Time
3:45pm
Mixer Location
Chemistry B101E
Additional Information

About the Talk:

The beneficial effects of fluorine substitution on the ADME properties of drugs has been widely recognized and its presence in pharmaceuticals and agrochemicals has increased dramatically due to the development of reagents for facile fluorination and trifluoromethylation. Conversely, the pentafluorosulfanyl (–SF5) group remains underexplored due to the challenges of working with traditional gaseous and highly toxic –SF5 precursors. The –SF5 group possesses both high electronegativity and high lipophilicity, has high thermal and hydrolytic stability, and has shown enhanced pharmacological properties of drugs when compared to trifluoromethyl substituted analogs. Current access to aryl–SF5 compounds is limited mainly to the simple thiophenols and derivatives amenable to the harsh oxidative-fluorination conditions necessary to generate the –SF5 group. Recent efforts have realized the ability of phenothiazine photocatalysts to reduce nontoxic SF6 to form a SF5 radical and fluoride anion after mesolytic cleavage. Ultimately, the photolytically generated SF5 radical was only shown to add anti-markovnikov to styrenes. The development of an easy-to-handle SF5 precursor that undergoes reversible photo-promoted homolysis may help spur the development of pentafluorosulfanylation methodologies. To that end, development of a competent radical trap in conjunction with a N-arylphenothiazine photocatalyst may allow for the reduction of SF6 and subsequent trapping of the generated SF5 radical to create a stable, photocleavable SF5 proradical reagent.