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Synthesis, Structure, and Properties of Unsaturated Thiacrown Ethers Possessing Sulfonium Groups

“…Finally, 3 a was completely converted into 1 . It is known that the equilibrium between sulfides and sulfonium salts exists under certain conditions [2a] . Although the triflate ion is known as a poor nucleophile, the nucleophilic addition of the triflate ion would occur at 100 °C to give demethylated products and methyl triflate.…”

A Practical Regioselective Synthesis of Alkylthio- or Arylthioindoles without the Use of Smelly Compounds Such as Thiols

“…Furthermore, earlier approaches used reagents prepared from smelly compounds such as thiols, and thus are not conveniently prepared in laboratories and factories. We focused on using dimethyl sulfoxide (DMSO)-trifluoroacetic anhydride (TFAA) to introduce a strong electron withdrawing dimethylsulfonyl group, [23][24][25][26][27] to allow reliable electrophilic aromatic substitution into indoles that addresses the above problems. Furthermore, this reagent is a non-smelly MeS + synthon for methylthiolation and thus can replace smelly thiols or sulfides.…”

“…Balenkova and colleagues 26,27) reported the introduction of a dimethylsulfonium group at the C 3 -position of indole using trifluoromethanesulfonylsulfonium triflate (Me dimethylsulfonium salt was de-methylated with Et 3 N or (NH 2 ) 2 CS in good to moderate yield (84-45%). However, this trifluoromethanesulfonylsulfonium triflate reagent is only applicable to N-methylated indole or stabilized indoles such as 2,2′-biindole and 2-phenylindole, and not applied to unprotected indole 1a.…”

Construction of α-Amino Azines via Thianthrenation-Enabled Photocatalyzed Hydroarylation of Azine-Substituted Enamides with Arenes

“…Regioselective aryl sulfonium salt formation with further transformation has emerged in recent years as a valuable approach for late-stage functionalization of arenes. , This general strategy also allows for the development of the novel disconnection for complex structures that are often elusive or currently impossible via transition metal-catalyzed C–H activation of undirected simple arenes . Inspired by the generation of aryl radicals from aryl thianthrenium salts, ,,,, we envisioned that the α-amino azines could be efficiently constructed via a sequence of aryl radical addition to azine-substituted enamides and protonation by employing aryl thianthrenium salts as the efficient aryl radical precursor under photoirradiation.…”