Solid-state organic reactions proceeding by pulverization: Oxidation and halogenation with iodosobenzene and inorganic solid-supports
摘要:
Pulverization-activation method was employed to accelerate solid-state organic reactions. Crushing and grinding of solid mixtures of hydrogen halide-treated silica gels, iodosobenzene and organic substrates in the absence of a solvent brought about smooth and rapid reactions to give halogenated and/or oxidized products in good yields. Various sulfides were smoothly converted to sulfonyl chlorides in one step in excellent yields. The surface of silica gel activated by pulverization serves as a reaction field on which reagent molecules can effectively encounter with each other. (C) 1998 Elsevier Science Ltd. All rights reserved.
carbon–heteroatom (C–P, C–O, C–S, and C–N) bonds via C–N cleavage of benzyl ammoniumsalts under transition-metal-free conditions was reported. The combination of t-BuOK and 18-crown-6 enabled a wide range of substituted benzyl ammoniumsalts to couple readily with different kinds of heteroatom nucleophiles, i.e. hydrogen phosphoryl compounds, alcohols, thiols, and amines. Good functional group tolerance was demonstrated
A new basic clay, synthesized by introducing 3-aminopropyltriethoxysilane into montmorillonite, catalyses the reaction between benzyl chloride and thiols to afford high yields of the corresponding sulfides.
carried out under transition-metal-free conditions, showing yields of asymmetric sulfides higher than 80%. Tertiary alkyl halides and aryl halides do not react with thiourea under formation of the corresponding isothiouroniumsalts; however, 5-bromopyrimidine and 2-bromopyrimidine lead to yields of 79.2% and 87.6%, respectively. This method is of significant importance from the both environmental and economic
1,2-Dibromotetrachloroethane: An Ozone-Friendly Reagent for the in Situ Ramberg–Bäcklund Rearrangement and Its Use in the Formal Synthesis of <i>E</i>-Resveratrol
作者:Stefan C. Söderman、Adrian L. Schwan
DOI:10.1021/jo3021852
日期:2012.12.7
Dibromotetrachloroethane (C2Br2Cl4) is demonstrated as a halogenating reagent for the one-pot conversion of sulfones to alkenes by way of the Ramberg–Bäcklundrearrangement. Dibromotetrachloroethane successfully replaces known ozone depleting agents CCl4, CBr2F2 and C2Br2F4. A formal synthesis of E-resveratrol is demonstrated using C2Br2Cl4.
已证明二溴四氯乙烷(C 2 Br 2 Cl 4)作为卤化试剂,可通过Ramberg-Bäcklund重排将砜一锅转化为烯烃。二溴四氯乙烷成功替代了已知的臭氧消耗剂CCl 4,CBr 2 F 2和C 2 Br 2 F 4。使用C 2 Br 2 Cl 4证明了E-白藜芦醇的正式合成。
Dealkylative intercepted rearrangement reactions of sulfur ylides
作者:Claire Empel、Katharina J. Hock、Rene M. Koenigs
DOI:10.1039/c8cc08821g
日期:——
Sulfur ylides are well-known to undergo sigmatropic rearrangementreaction. Herein, we describe a novel reactivity of sulfur ylides, which provides access to the product of a formal functional group metathesis upon dealkylative interception of the rearrangement process. Using a simple iron catalyst and in situ generated diazoalkanes this method provides access to α-mercaptoacetonitrile derivatives