Pyridine tetrafluoro-λ⁶-sulfanyl chlorides: spontaneous addition to alkynes and alkenes in the presence or absence of photo-irradiation

Abstract

A radical addition reaction of Py-SF4Cl to alkynes and alkenes provide pyridine-SF4-alkenes and pyridine-SF4-alkanes under blue LED light irradiation or absence of light irradiation in CPME or without solvent.

(Hetero)aryl‐SVI Fluorides: Synthetic Development and Opportunities

“…This procedure is an excellent alternative to BEt 3 ‐catalyzed processes, as the borane is often the source of undesired side reactivity or substrate decomposition. In agreement with previous reports, the authors proposed a radical process to explain the reactivity observed [53] …”

“…In agreement with previous reports, the authors proposed a radical process to explain the reactivity observed. [53]…”

Recent Advances in the Synthesis and Medicinal Chemistry of SF5 and SF4Cl Compounds

“…Scheme 20 Synthesis pf pyridine-SF4-λ 6 -sulfanyl-alkenes and -alkanes. 23 Key: CPME = cyclopentyl methyl ether A safe, practical and scalable synthesis of SF5Cl in n-hexane under gas-reagent-free conditions was reported by Qing et al (Scheme 21), 24a who optimized the method previously described by Togni et al 24b The reaction of sulphur powder, dry KF and TCICA in the dark, affords SF5Cl along with SO2F2 and SOF2 as by-products. SF5Cl can be easily purified by extraction in n-hexane and the resulting solution can be stored for months without noticeable decomposition.…”

“…Scheme 20 Synthesis of pyridine-SF 4 - 6 -sulfanylalkenes and -alkanes. 23 CPME: Cyclopentyl methyl ether.…”

“…A single example of preparation of PhSF 5 from (PhS) 2 was reported as proof of concept for the use of [NEt 3 Me][ClF 4 ] as a fluorinating and oxidation reagent, as the latter had become accessible on a gram scale using a novel methodology (based on the reaction of NEt 3 Me + Clwith 2 equivalents of F 2 in acetonitrile). 22 A detailed study on the synthesis of pyridine-SF 4 - 6 -sulfanylalkenes and -alkanes was reported by Shibata et al 23 The method is based on the addition reaction of pyridinetetrafluoro- 6 -sulfanyl chlorides (Py-SF 4 Cl) to alkynes and alkenes, which occurred spontaneously even in total darkness and without solvents but was positively influenced by exposure to light (e.g., blue LEDs). A series of SF 4bridged pyridines were efficiently synthesized in good to excellent yields (Scheme 20).…”