A Convenient Method for the Synthesis of α-Imidostyrenes from Styrenes and Imides via Diphenylstyrylsulfonium Salts
Styrenes having a hydrogen atom at the α-position reacted with diphenyl(trifluoromethanesulfonyloxy)sulfonium triflate (1) to form diphenylstyrylsulfonium triflates 2 that were in turn converted into the corresponding α-imidostyrenes on treatment with sodium or potassium salts of cyclic imides.
Cobalt modified N-doped carbon nanotubes for catalytic C=C bond formation via dehydrogenative coupling of benzyl alcohols and DMSO
The development of heterogeneous, cost-effective and environmentally benign catalysts to construct C=C bonds is highly desirable. We report here Co@N-doped carbon nanotubes (Co@NCNT) as a catalyst for a novel synthesis of styryl sulfides via dehydrogenative coupling of benzyl alcohols and DMSO under anaerobic conditions. This reaction maintains high atom efficiency as the C=C bond is formed without the cracking of the C-S bond. We proposed that Co modified N-doped carbon sites are the active sites, different from traditionally believed metal centers for dehydrogenative C-C coupling. Moreover, the Co@NCNT catalyst could be easily separated and recycled for at least six runs. This work opens up a new application of metal-N-C catalysts in C=C bond-forming reactions in synthetic chemistry.
Study of SNAr reactions of halobenzenes with imidazole under ultrasonic and microwave irradiation
Nucleophilic aromatic substitution reactions with imidazole of haloarenes having strongly electron-withdrawing groups were studied under ultrasonic and microwave irradiations. The course of the SNAr reactions was found to be strongly dependent on the electron-withdrawing properties of the substituents as well as on the leaving ability of the halogen atom. Microwave irradiation allowed to shorten the reaction time and to increase the yields compared with ultrasonic irradiation. Springer-Verlag 2004.
Meciarova, Maria,Podlesna, Janka,Toma, Stefan
p. 419 - 423
(2007/10/03)
Mg-promoted stereoselective desulfonation of β-arylvinyl sulfone derivatives
β-Arylvinyl ρ-tolylsulfones, easily prepared from base-catalyzed condensation of aromatic aldehydes with a variety of ρ-tolylsulfones, were efficiently transformed to the corresponding (E)-β-substituted aromatic olefins in a stereoselective manner through Mg-promoted reduction. The reaction may be initiated through electron transfer from Mg metal to the vinyl sulfones to give the corresponding anionic species followed by stereoselective elimination of a sulfonyl group.
Desulfonylation of α-Methylthio-α,β-unsaturated Sulfones. A New Route to One Carbon Homologation of Aromatic Aldehydes
α-Methylthio-α,β-unsaturated sulfones 3 prepared from aromatic aldehydes 1 and sulfone 2 react with sodium hydrogen telluride in ethanol to undergo reductive desulfonylation to give vinyl sulfides 4 with certain extent of stereospecificity.A new route to one carbon homologation of aromatic aldehydes 1 to 5 is achieved by hydrolysis of 4 with titanium tetrachloride.
Huang, Xian,Zhang, Han-Zhong
p. 42 - 43
(2007/10/02)
More Articles about upstream products of 25650-51-5