Organic reactions mediated by electrochemically generated ArS+

Abstract

Low-temperature electrochemical oxidation of ArSSAr was carried out to generate a pool of "ArS(+)". Spectroscopic studies ((1)H NMR and CSI-MS) of the resulting solution revealed the accumulation of ArS(ArSSAr)(+). The resulting "ArS(+)" pool reacted with alkenes and alkynes to give diarylthio-substituted products. The "ArS(+)" pool rapidly reacted with thioacetals to give the corresponding alkoxycarbenium ion pools, which reacted with various carbon nucleophiles (indirect cation pool method). The reaction of the alkoxycarbenium ion pools with stilbene derivatives in the presence of ArSSAr gave thiochroman derivatives. In addition to such stoichiometric reactions, a catalytic amount of "ArS(+)" serves as an initiator and a chain carrier of some cationic chain reactions involving intramolecular carbon-carbon bond formation. In situ generation of "ArS(+)" by electrochemical oxidation of ArSSAr with a catalytic amount of electricity in the presence of a substrate is also effective for such cationic chain reactions.

Synthetic Organic Electrochemical Methods Since 2000: On the Verge of a Renaissance

“…505–510 The thiirane could be opened directly with hard nucleophiles such as fluorides or alkoxides. Nevertheless, due to the presence of disulfides in solution, treatment of the episulfonium with soft nucleophiles led to the formation of vicinal disulfides instead.…”

Electrons and Holes as Catalysts in Organic Electrosynthesis

“…[36] ArSSAr and serves as a reagent for the generation of organic cations ("indirect cation-pool method"). [37] After cyclization of 13, the resulting carbocation 14 reacts with ArSSAr to form the product 15. Since a thioaryl group is present in the substrate, "ArS + " is continuously regenerated in a cationic chain reaction (both electric charge and ArSSAr are employed in catalytic amounts).…”

“…The intramolecular bond formation between a thioacetal carbon and an olefin unit in substrates of type 12 is initiated by reaction with anodically generated ArS(ArSSAr) + (an equivalent of ArS + ) and leads to alkoxycarbenium intermediate 13 . The ArS(ArSSAr) + species can be generated by low‐temperature electrochemical oxidation of ArSSAr and serves as a reagent for the generation of organic cations (“indirect cation‐pool method”) . After cyclization of 13 , the resulting carbocation 14 reacts with ArSSAr to form the product 15 .…”

A quantitative approach to nucleophilic organocatalysis

“…The reactivity scales, developed on this basis, have not only be employed for designing organic syntheses [6–18], but were also helpful for rigorous examinations of general concepts of organic reactivity, such as the “Reactivity Selectivity Principle” [19], the “HSAB Treatment of Ambident Reactivity” [20] and the changes of mechanisms in nucleophilic aliphatic substitutions [21–22]. In this essay, we will illustrate applications of Eq.…”