Synthesis of sulfonyl chlorides and thiosulfonates from H2O2–TiCl4
作者:Kiumars Bahrami、Mohammad M. Khodaei、Donya Khaledian
DOI:10.1016/j.tetlet.2011.11.052
日期:2012.1
A new method is described for the oxidative chlorination of thiols to sulfonylchlorides using titanium tetrachloride in combination with the oxidant hydrogen peroxide. Direct conversion of thiols into their corresponding thiosulfonates is also reported. Good to excellent yields, short reaction times, high efficiencies, cost-effectiveness, and, facile isolation of the desired products make the present
also effective in preparing sulfonyl fluorides from disulfides under the similar reaction conditions. Sulfonylchlorides or sulfonyl bromides were effectively obtained from the reaction of disulfides with 6 equiv of either N-chlorosuccinimide or N-bromosuccinimide in acetonitrile/water (10:1) at room temperature. Some other electrophilic chlorinating or brominating reagents are also able to be used instead
Straightforward chemoselective access to unsymmetrical dithioacetals through a thiosulfonate homologation-nucleophilic substitution sequence
作者:Laura Ielo、Veronica Pillari、Natalie Gajic、Wolfgang Holzer、Vittorio Pace
DOI:10.1039/d0cc04896h
日期:——
presented for the preparation of rare unsymmetrical dithioacetals. The judicious selection of thiosulfonates as convenient sulfur electrophilic sources – upon the homologation event conducted on an intermediate α-halothioether – guarantees the release of the non-reactive sulfonate group, thus enabling the subsequent nucleophilic displacement with an external added thiol [(hetero)aromatic and/or aliphatic]
A simple, efficient, and odorless deborylthiolation of aryl- and alkenylborons with thiosulfonates has been achieved under mild conditions using a copper catalyst.
Under anaerobic conditions S-nitrosothiols 1a-e undergo thermal decomposition by homolytic cleavage of the S-N bond; the reaction leads to nitric oxide and sulfanyl radicals formed in a reversible manner. The rate constants, k(t), have been determined at different temperatures from kinetic measurements performed in refluxing alkane solvents. The tertiary nitrosothiols 1c (k1(69 degrees C) = 13 x 10(-3)
在厌氧条件下,S-亚硝基硫醇1a-e通过SN键的均相裂解而发生热分解。该反应导致可逆地形成一氧化氮和亚硫烷基。速率常数k(t)已在不同温度下根据在回流烷烃溶剂中进行的动力学测量确定。叔亚硝基硫醇1c(k1(69摄氏度)= 13 x 10(-3)min(-1))和1d(k1(69摄氏度)= 91 x 10(-3)min(-1))分解更快比主要亚硝基硫醇1a(k1(69摄氏度)= 3.0 x 10(-3)min(-1))和1b(k1(69摄氏度)= 6.5 x 10(-3)min(-1))。活化能(E#= 20.5-22.8 Kcal mol(-1))已根据Arrhenius公式计算得出。在有氧条件下,S-亚硝基硫醇1a-e的降解是由N2O3催化的自催化链分解过程引起的。后者通过双氧与内源性和/或外源性一氧化氮反应形成。通过去除内源性一氧化氮或存在抗氧化剂(例如对甲酚,β-苯乙烯和BHT),强