Photoinduced Oxidative Cross-Coupling for O-S Bond Formation: A Facile Synthesis of Alkyl Benzenesulfonates
We have developed a photoinduced oxidative cross-coupling of thiophenols with alcohols for O-S bond formation. The protocol uses visible light, a metal-free photocatalyst, and oxygen as the oxidant for the selective synthesis of alkyl benzenesulfonates; no ligand co-additive is necessary. Mechanistic studies suggested that the disulfide and alkyl benzenesulfinate are involved as intermediates and that the transformation proceeds by a radical pathway.
Perchlorate Esters. Part 3. Correlation of the Rates of Reaction of Arenesulphonate Ions with Methyl Perchlorate in Acetonitrile
Second-order rate coefficients for the reactions of acetonitrile solutions of tetra-n-butylammonium benzensulphonate and seven meta- and para-substituted derivatives with methyl perchlorate, at 0.3 deg C lead to a Hammet ρ value (-1.10 +/- 0.04) essentially identical to those previously reported for reactions with other powerful methylating agents.When silver ion is substituted for tetra-n-butylammonium ion, the second-oreder rate coefficients become concetration dependent and the fall of with increasing salt concetration can be rationalised on the basis of only free anions being reactive.The calculated degrees of dissociation are applied tothe previously studied silver0ion assisted reaction of silver toluene-p-sulphonate with methyl iodide.
Kevill, Dennis N.,Lin, Gloria Meichia L.,Bahari, Mohd S.
p. 49 - 52
(2007/10/02)
CORRELATION OF THE RATES OF REACTION OF ARENESULFONATE IONS WITH THE TRIMETHYLOXONIUM ION IN ACETONITRILE
The kinetics of the reactions between trimethyloxonium hexafluorophosphate and a series of tetra-n-butylammonium arenesulfonates have been studied in acetonitrile at -23.4 deg C.With the oxonium salt concentration at about 0.01 M, two series of runs were carried out; Hammett plots of the second-order rate coefficients led to ρ values of -1.18 +/- 0.04 for 0.04 M arenesulfonate salt and -1.07 +/- 0.02 for 0.16 M arenesulfonate salt.Solvolysis kinetics for the trimethyloxonium ion in acetonitrile are also reported.