- Palladium-Catalyzed Reductive [5+1] Cycloaddition of 3-Acetoxy-1,4-enynes with CO: Access to Phenols Enabled by Hydrosilanes
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A new palladium-catalyzed reductive [5+1] cycloaddition of 3-acetoxy-1,4-enynes with CO, enabled by hydrosilanes, has been developed for delivering valuable functionalized phenols. This methodology employs hydrosilanes as the external reagent to facilitate the [5+1] carbonylative benzannulation. The reaction is a conceptually and mechanistically novel carbonylative cycloaddition route for the construction of substituted phenols, through the formation of four new chemical bonds, with excellent functional-group tolerance.
- Li, Jin-Heng,Luo, Shenglian,Song, Ren-Jie,Wu, Li-Jun
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supporting information
p. 13308 - 13312
(2018/09/21)
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- An Efficient Protecting-Group-Free Synthesis of Vinylic Sulfoximines via Horner-Wadsworth-Emmons Reaction
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Herein, we report a convenient synthesis of aryl-substituted (E)-vinylic NH-sulfoximines via the Horner-Wadsworth-Emmons reaction without the use of protection-deprotection group strategies.
- Chinthakindi, Praveen K.,Nandi, Ganesh Chandra,Govender, Thavendran,Kruger, Hendrik G.,Naicker, Tricia,Arvidsson, Per I.
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p. 1423 - 1427
(2016/05/24)
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- Synthesis of Sulfoxides by the Hydrogen Peroxide Induced Oxidation of Sulfides Catalyzed by Iron Tetrakis(pentafluorophenyl)porphyrin: Scope and Chemoselectivity
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The oxidation of sulfides with H2O2 catalyzed by iron tetrakis(pentafluorophenyl)porphyrin in EtOH is an efficient and chemoselective process. With a catalyst concentration 0.03-0.09% of that of the substrate, sulfoxides are obtained with yields generally around 90-95% of isolated product. With vinyl and allyl sulfides, no epoxidation is observed. With a catalyst concentration between 0.09% and 0.25% of that of the substrate, sulfones are obtained in almost quantitative yield and with the same high chemoselectivity observed in the synthesis of sulfoxides.
- Baciocchi, Enrico,Gerini, Maria Francesca,Lapi, Andrea
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p. 3586 - 3589
(2007/10/03)
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- A conjugate addition/sulfoxide elimination route to allylic difluorophosphonates
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Cerium-mediated conjugate additions of (diethoxyphosphinoyl) difluoromethyllithium to cyclic vinyl sulfoxides proceeded smoothly; thermal sulfoxide elimination afforded the products of formal vinylation, attaching the difluoromethylenephosphonato group to an alkenyl carbon atom. With acyclic vinyl sulfoxides, the addition occurred in moderate to poor yield. Addition failed completely in the absence of cerium(III) chloride, and was facilitated by an excess of the reagent.
- Blades, Kevin,Percy, Jonathan M.
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p. 9085 - 9088
(2007/10/03)
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- Steric and Resonance Effects on the Kinetics of Oxidation of Organic Sulfides by Quinolinium Fluorochromate
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Kinetics of oxidation of dialkyl, alkyl phenyl and benzal methyl phenyl sulfides to their sulfoxides by quinolinium fluorochromate (QFC) have been followed in aqueous acetic acid. The order of the reaction is found to be one each with respect to QFC, H3O+ and the sulfide. Increase in the dielectric constant of the medium decreases the rate, while variation in ionic strength has no perceptible change in the rate. The steric effect plays a dominant role to decide the rate of the reaction rather than the inductive effect. In the case of benzal methylphenyl sulfide, the larger rate is due to the resonance effect. Attack of protonated QFC on the organic sulfide in a slow step, is rate-determining one.
- Karunakaran, Kulandaivelu,Gurumurthy, Rajagopala,Elango, Kuppannagounder Pitchaimuthu
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p. 297 - 299
(2007/10/03)
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- ACTIVATION DE LA LIAISON C-H FAIBLEMENT ACIDE PAR ADSORPTION SUR KF-Al2O3
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Condesation of poorly acidic carbon compounds (pka 18-30) with benzaldehyde was achieved by adsorption without solvent on KF-Al2O3.KF-Al2O3 appears as a stronger base than KF.
- Villemin, Didier,Ricard, Michele
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p. 1059 - 1060
(2007/10/02)
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