Abstractmagnified imageA pronounced catalytic effect of sodium dodecyl sulfate (SDS) was observed on thein situproduction ofS‐alkylisothiouronium saltsviathe reaction of primary, allyl and benzyl halides with thiourea in SDS droplets .Hydrolysis of the generatedS‐alkylisothiouronium salts in the palisade layer of the droplets produces the corresponding thiol moieties which are immediately added to the electron‐deficient olefins that are present in the micellar core to produce the thia‐Michael adducts. The entire route is an almost odorless process. The yields of the products are good to excellent and the method is applicable to large‐scale operation without any problem.
Catalyst-Free Conjugated Addition of Thiols to α,β-Unsaturated Carbonyl Compounds in Water
作者:Gopal L. Khatik、Raj Kumar、Asit K. Chakraborti
DOI:10.1021/ol060846t
日期:2006.5.1
[reaction: see text] Catalyst-free conjugateaddition of thiols to alpha,beta-unsaturated carbonylcompounds in water is reported. beta-Sulfido carbonylcompounds were formed at room temperature, in short times and with excellent chemoselectivity. Competitive dithiane/dithiolane formation, transesterification, and ester cleavage were not observed. Water played a dual role in simultaneously activating
Synthesis and application of modified silica sulfuric acid as a solid acid heterogeneous catalyst in Michael addition reactions
作者:Mohammad Ali Zolfigol、Hojat Veisi、Farajollah Mohanazadeh、Alireza Sedrpoushan
DOI:10.1002/jhet.659
日期:2011.7
Modified silicasulfuricacid (MSSA) as a new type of silicasulfuricacid was prepared and effectively used in the conjugate addition of indole, pyrrole, and thiols with Michael acceptors under mild conditions at room temperature. Also, MSSA was used as a catalyst for the synthesis of 1,1,3‐tri‐indolyl compounds in good to excellent yield at room temperature. J. Heterocyclic Chem., (2011).
It was found that sodium salt of 1,2-benzisothiazole-3(2H)-thione 1,1-dioxide (thiosaccharin) readily reacted with alkyl halide affording 3-(alkylthio)-1,2-benzisothiazole 1,1-dioxide (3). Treatment of 3 with piperidine produces the corresponding alkanethiol in situ quantitatively and subsequent treatment with various electrophiles gives the corresponding sulfides and thiocarboxylic S-esters in good yields.
Fluoroboric acid adsorbed on silica-gel (HBF4–SiO2) as a new, highly efficient and reusable heterogeneous catalyst for thia-Michael addition to α,β-unsaturated carbonyl compounds
作者:Gaurav Sharma、Raj Kumar、Asit K. Chakraborti
DOI:10.1016/j.tetlet.2008.04.144
日期:2008.6
found to be a new and highly efficient heterogeneouscatalyst for thia-Michael addition to α,β-unsaturated carbonyl compounds under solvent-free conditions. In the case of 1,3-diaryl-2-propenones, the reactions are best carried out in MeOH. The rate of thia-Michael addition was dependent on the steric hindrance at the β-carbon of the α,β-unsaturated carbonyl substrate as well as surrounding the thiol
Scope and limitations of HClO4–SiO2 as an extremely efficient, inexpensive, and reusable catalyst for chemoselective carbon–sulfur bond formation
作者:Gopal L. Khatik、Gaurav Sharma、Raj Kumar、Asit K. Chakraborti
DOI:10.1016/j.tet.2006.11.050
日期:2007.1
cyclic and acyclic α,β-unsaturatedketones afforded excellent yields of the corresponding β-sulfidocarbonyls after 2 min to 2 h. In the case of dithiols, the bis-thia-Michael adducts were formed. The rate of the reaction was found to be dependent on the electronic and steric factors of the α,β-unsaturatedketones and the thiols. A substituent at the β-carbon of the α,β-unsaturatedketone offered steric