Water oxidation by Brønsted acid-catalyzedin situgenerated thiol cation: dual function of the acid catalyst leading to transition metal-free substitution and addition reactions of S–S bonds

Abstract

An unprecedented water oxidation reaction by a small organic molecule, i.e., the thiol cation generated in situ by Brønsted acid-catalyzed heterolytic cleavage of S-S bond of a disulfide, is observed...

Copper-Catalyzed Hydroxylation of Aryl Halides Using Hydroxypicolinamide Ligands

“…The para -hydroxyl group serves multiple purposes as an internal phase transfer agent, allows this ligand to potentially reduce Cu(II) back to Cu(I) after an oxidation event, and by minimizing ligand arylation. The 4-hydroxy moiety seems to allow for the redox of copper to occur perhaps through formation of a quinone byproduct, analogous to other related phenols capable of undergoing oxidation to a quinone or quinone methide . HMPS consistently provided full conversion under rigorously degassed conditions in DMSO, sulfolane, and alcohol-blended systems unlike MPBS (discussion below in screening Cu sources with HMPS, Table ).…”

“…The electronic nature of groups on the aniline ring plays a key role in tuning ligand efficiency. Increased reactivity was observed with increasing electron richness of the aniline ring system (ligands L-E and L-F 23 ). Placing a hydroxyl group para to the aniline that would be formally deprotonated under the reaction conditions provided the greatest enhancement in reactivity and selectivity (L-G�HMPS).…”

Thiocyanation of Allylic Alcohols Promoted by Trifluoroacetic Acid

“…[36][37][38][39] Although the hydroxyl of alcohol is a weak leaving group, acidic conditions can promote its leaving ability. [40][41] Based on some reports of alcohol activation and our dedicated works, [35][36][37][38][39][40][41][42][43][44][45][46] we report a more efficient carbocation-induced pathway to directly con- www.eurjoc.org struct versatile organic allylic thiocyanates with addition of TFA under the mild, maneuverable, metal-free and oxidant-free conditions (Scheme 1).…”

Carbon‐Sulfur Bond Formation via Ipso Nucleophilic Substitution of Electron‐Deficient Benzenesulfonic Acid with Thiol

“…[20] Recently, the same group achieved transition metal-free thioether synthesis via nucleophilic substitution using a catalytic amount of KHSO 4 , thiols or disulfides, and alcohols. [21] Badsara et al reported the CÀ S coupling of dihydropyridines with various thiols in the presence of Cs 2 CO 3 in DMSO. [22] However, these methods bear drawbacks, such as the metal catalysts being expensive and harmful to the environment, requiring elevated temperatures, and producing many side products.…”