Gold‐Catalyzed, Iodine(III)‐Mediated Direct Acyloxylation of the Unactivated C(sp³)–H Bonds of Methyl Sulfides

Abstract

The gold‐catalyzed, iodine(III)‐mediated direct oxidative acyloxylation of the C(sp3)–H bonds of methyl sulfides for the synthesis of various α‐thioaryl and α‐thioalkyl ester derivatives was discovered. Bis(acyloxy)iodobenzene proved to be an efficient reagent to activate the sulfur atom as an in situ directing group for α‐C(sp3)–H functionalization. The attractive features of this protocol include short reaction times, low catalyst loading, and in situ activation of adjacent C(sp3)–H bonds of the sulfur atom.

Ligand exchange of aryl iodine dicarboxylates to form reagents with differing solubilities

“…Solubility of hypervalent iodides in a variety of solvents entry substrate solvent solubility (mg/mL) a solubility (mmol/mL) % RSD Hypothesizing that a longer aliphatic chain of the carboxyl group of the hypervalent iodide would increase solubility in less polar solvents, butyric acid derived 3 was synthesized and its solubility was measured. Compound 3 is known in the literature, [25][26][27][28][29][30][31] but it is mostly employed in reactions where the carboxylic acid moiety of the HVI is transferred. The solubility of 3 has not been reported.…”

Gold‐Catalyzed Direct C(sp3)−H Acetoxylation of Saturated Hydrocarbons

“…In addition, very similar reaction conditions were reported by Guo et al . for the acetoxylation of C(sp 3 )−H bonds of methyl sulfides [12] . Notably this reaction has been proposed to proceed via the initial formation of a sulfonium salt without the involvement of the gold catalyst.…”

Recent progress in catalytic acyloxylation of C(sp3)‐H bonds

“…Yuan and Yang with coworkers presented the first example of direct α ‐C(sp 3 )‐H acyloxylation of sulfides in the presence of hypervalent iodine (III) reagents as oxidants and PPh 3 AuCl as catalyst. [ 101 ] A series of alkyl‐ and aryl methyl sulfides of the type 157 was converted to the corresponding acyloxy products 158 in moderate to good yields (Scheme 24). The reaction proceeded within 1–2 h at low catalyst loadings (0.5 mol.…”