Thiosulfonylation of Unactivated Alkenes with Visible-Light Organic Photocatalysis

Abstract

A metal-free method for the vicinal thiosulfonylation of unactivated alkenes with thiosulfonates using 9-mesityl-10-methylacridinium perchlorate as the photo-organocatalyst with visible-light irradiation has been developed. The method can be performed in dimethyl carbonate under air at room temperature and features a broad functional group compatibility. Metrics indicate the green potential of the developed versus the state-of-the-art methodologies. Mechanistic studies revealed no single electron transfer but involvement of an energy transfer from the excited photoorganocatalyst to thiosulfonate reactant, subsequently providing a sulfenyl and a sulfonyl radical via homolytic cleavage.

Visible-Light-Triggered Sulfonylation/Aryl Migration/Desulfonylation and C–S/Se Bond Formation Reaction: 1,2,4-Trifunctionalization of Butenyl Benzothiazole Sulfone with Thiosulfonate/Selenosulfonates

“…On the basis of the above experiments and reference related literature, 16,24 we propose a plausible reaction mechanism in Figure 6. After Eosin Y absorbs light energy, it changes from a ground state to the excited state, which transfers the energy to the thiosulfonate to give its corresponding excited state.…”

“…In 2019, the Zhu group realized the 1,6-difunctionalization of olefins by thiosulfonate through 1,5-HAT . In 2020, the Maes group used Mes-Acr + -Me ClO 4 – to achieve the thiosulfonylation of nonactivated alkenes . Although the previously described works have been well studied, they were limited to only the 1,2-difunctionalization or 1,6-difunctionalization of olefins.…”

“…− to achieve the thiosulfonylation of nonactivated alkenes. 16 Although the previously described works have been well studied, they were limited to only the 1,2-difunctionalization or 1,6-difunctionalization of olefins. Inspired by the elegant 1,4difunctionalization of 1,3-dienes and 1,3-enynes, we reasoned that we could achieve the 1,4-thiosulfonylation of new functional olefin compounds to explore the 1,2,4-trifunctionalization reaction of olefin derivatives through aryl migration/ desulfonylation strategies.…”

Synthesis, Reactivity and Activation Modes of Fluoroalkyl Thiosulfonates and Selenosulfonates

“…Finally, a photocatalyzed alternative was developed by the group of Maes in 2020 (Scheme 6E). [26] If only one example is reported (17), it is however interesting to note the efficiency of such process with a very low catalyst loading.…”

Visible-light-induced dehydrogenative sulfonylation of tertiary amines under transition-metal- and photocatalyst-free conditions

“…17 Under irradiation with visible light, D underwent homolytic cleavage of the S–S bond to afford a sulfenyl radical E . 18 The radical E then abstracted hydrogen from the tertiary amine radical cation C to generate an intermediate F , 19 which was then converted into enamine G by the deprotonation with 4-methylbenzenesulfinate. 14,20 Enamine G combined with the sulfonyl radical to give a radical H followed by a deprotonation radical process to generate the target product 3a .…”