Metal‐Free Air Oxidation of Thiols in Recyclable Ionic Liquid: A Simple and Efficient Method for the Synthesis of Disulfides

Abstract

An efficient procedure for the oxidative coupling of alkyl, aryl and heteroaryl thiols with atmospheric oxygen is reported. The methodology utilizes BMIM-BF 4 as a recyclable

Switching reaction pathways of trifluoromethylated thiobenzanilides by choice of different oxidative systems

“…It is a common knowledge that molecules containing a disulfide moiety play an important role in biochemistry. However, the oxidative dimerization of thiobenzanilides was less reported than the related thiols [13]. After investigating the CAN-oxidative cyclization, we then turned our attention to dimerization of the thiobenzanilides by PIDA.…”

“…19 F NMR spectra were taken on a Bruker AM-300 (282 MHz) spectrometer using CFCl 3 as external standard. 13 C NMR spectra were taken on a Bruker AM-400 (100 MHz) spectrometer. IR spectra were obtained with a Nicolet AV-360 spectrophotometer.…”

7.28 Oxidation of Sulfur, Selenium, and Tellurium

“…This system proved to be significantly more efficient that the previously reported aerobic oxidation of thiols catalyzed by Co(II)-phthalocyanines dissolved in BMIM-BF 4 . 15 A base-free BMIM-SeO 2 (OMe) protocol for the aerobic oxidation of symmetrical aryl, alkyl, and functionalized thiols under microwave irradiation has been found to be suitable for reuse up to five cycles affording the products in good-to-high yield. 16 Gold nanoparticles supported on CeO 2 were recently reported to smoothly promote the oxidation of aromatic and heterocyclic thiols to disulfides under air in the absence of solvent or in neutral water solution.…”

Title Pages

“…The quantitative reduction of enamines with methanol under microwave irradiation 42 seems almost 'too good to be true', as does a simple, eco-friendly isomerization of allyl acetates with silica gel 43 . Note, too: the aerobic photooxidation of methylarenes with tetrabromomethane as catalyst 44 ; a simple aerobic oxidation of mercaptans in ionic liquids 45 ; a metal-free reductive conversion of ketones and aldehydes to ethers via tosylhydrazones 46 ; and a remarkable phosphine-catalyzed asymmetric boration of enones without the familiar copper catalyst 47 . A mild and environmentally friendly oxidative cleavage of β-diketones to carboxylic acids has also been achieved cleanly with hydrogen peroxide and an iodide source 48 , while the unusual β-fragmentation of 3-ethylenesulfonylamines to N-sulfonylaldimines with phenyl iodosoacetate and iodine effectively reverses a stalwart in organosynthesis: nucleophilic allylation of the CWN bond 49 .…”