Transition metal-free α-C_sp3–H oxidative sulfuration of benzyl thiosulfates with anilines to form N-aryl thioamides

Abstract

A transition metal-free synthesis of N-aryl thioamides was realized by the oxidative sulfuration of Bunte salts in DMSO with anilines.

Copper-Catalyzed Oxidative Thioamination of Maleimides with Amines and Bunte Salts

“…After thorough optimization of reaction conditions, the reaction was conducted using CuI as the catalyst, DCE as the solvent, and oxygen as the green oxidant at 100 °C, the desired product 4a was isolated in 83% yield (Table , entry 1). It was noteworthy that sulfenylation of maleimides, thia-Michael addition of Bunte salt with maleimides, and α-amination of Bunte salt with amines were not observed at all during optimization of the reaction conditions. It was found that the choice of copper catalyst was a critical success factor for this reaction.…”

Selective synthesis of α-organylthio esters and α-organylthio ketones from β-keto esters and sodiumS-organyl sulfurothioates under basic conditions

“…This result demonstrated the first insight into the selective formation of the carbonyl compound 3a based on the amount of base. With this result in hand and considering 4 equivalents of NaOH as ideal for the formation of 3a, we then explored the influence of diverse solvents (Table 1, entries [12][13][14][15][16][17][18][19]. It can be observed that none of the tested solvents affected the reaction positively.…”

“…We next surveyed a range of differently substituted β-keto esters in the reaction with sodium S-benzyl sulfurothioate (2a, Table 2, entries [11][12][13][14][15][16][17][18]. This protocol enabled the synthesis of various α-benzylthio esters 3k-r bearing alkyl, allyl, and benzyl groups directly bonded to the oxygen atom of the ester group.…”

“…Therefore, they have been actively studied as precursors for the preparation of diverse sulfur-containing compounds [1]. These recent findings include their use in direct sulfenylation reactions of electron-rich N-heterocycles [2][3][4], decarboxylative cross-coupling reactions with propiolic acid derivatives [5], Michael addition reaction [6], cross-couplings catalyzed by Pd [7] and Cu salts [8,9], the preparation of symmetrical and nonsymmetrical disulfides [10,11], and the synthesis of β-acetamido sulfides by the acetamidosulfenylation of alkenes [12], among others [13][14][15].…”