Photoredox Catalytic α‐Alkoxypentafluorosulfanylation of α‐Methyl‐ and α‐Phenylstyrene Using SF₆

Abstract

SF6 was applied as pentafluorosulfanylation reagent to prepare ethers with a vicinal SF5 substituent through a one‐step method involving photoredox catalysis. This method shows a broad substrate scope with respect to applicable alcohols for the conversion of α‐methyl and α‐phenyl styrenes. The products bear a new structural motif with two functional groups installed in one step. The alkoxy group allows elimination and azidation as further transformations into valuable pentafluorosulfanylated compounds. These results confirm that non‐toxic SF6 is a useful SF5 transfer reagent if properly activated by photoredox catalysis, and toxic reagents are completely avoided. In combination with light as an energy source, a high level of sustainability is achieved. Through this method, the proposed potential of the SF5 substituent in medicinal chemistry, agrochemistry, and materials chemistry may be exploited in the future.

Multi‐Photon Excitation in Photoredox Catalysis: Concepts, Applications, Methods

“…Many synthetic applications of multi‐photon‐excitation‐based photoredox catalysis have been developed for reductive transformations, but comparatively little work has been reported for oxidations . Most of the concepts discussed above are readily adaptable to oxidative transformations, and a study discussing an oxidative equivalent of the concept from Section 3 appeared recently . Possible issues with the degradation of radical‐cation intermediates and their excited‐state lifetimes similar to those discussed for radical anions in reductions (Sections 3 and 9) as well as with photocatalyst stability (Section 8) will have to be considered thoroughly under oxidizing conditions.…”

Reactivity of Binary and Ternary Sulfur Halides towards Transition‐Metal Compounds

“…Wagenknecht and co‐workers utilized the strongly reducing photocatalyst N ‐phenylphenothiazine to photolytically activate both SF 6 and a styrene derivative as substrate . The generated SF 5 radical and radical cation of the styrene substrate combine to yield a cationic SF 5 intermediate.…”

Multiphotonen‐Anregung in der Photoredoxkatalyse: Konzepte, Anwendungen und Methoden

“…Die meisten der hier vorgestellten Konzepte können problemlos für oxidative Umwandlungen angepasst werden. Eine Studie mit einer oxidativen Variante des Konzepts aus Abschnitt 3 ist beispielsweise kürzlich erschienen . Mögliche Probleme durch Zerfallsprozesse von Radikalanionen und deren Lebenszeiten im angeregten Zustand (Abschnitte 3 und 9) oder auch die Stabilität von Photokatalysatoren (Abschnitt 8) müssen auch unter oxidierenden Bedingungen gründlich analysiert und berücksichtigt werden.…”