Anhydrous ferric chloride adsorbed on silica gel induced ring enlargement of tertiary cyclobutanols
作者:A. Fadel、J. Salaün
DOI:10.1016/s0040-4020(01)96434-8
日期:1985.1
The reagent obtained by mixing anhydrous FeCl3 and silica gel induced, in dry medium, dehydration and specific C4 → C5 ringenlargement of tertiary cyclobutanols, cyclization of olefinic alcohols and cleavage of tetrahydropyranyl ethers.
Hydrogenation of arenes and N-heteroaromatic compounds over ruthenium nanoparticles on poly(4-vinylpyridine): a versatile catalyst operating by a substrate-dependent dual site mechanism
作者:Minfeng Fang、Nataliya Machalaba、Roberto A. Sánchez-Delgado
DOI:10.1039/c1dt10801h
日期:——
A nanostructured catalyst composed of Ru nanoparticles immobilized on poly(4-vinylpyridine) (PVPy) has been synthesized by NaBH4 reduction of RuCl3·3H2O in the presence of the polymer in methanol at room temperature. TEM measurements show well-dispersed Ru nanoparticles with an average diameter of 3.1 nm. Both powder XRD patterns and XPS data indicate that the Ru particles are predominantly in the zerovalent state. The new catalyst is efficient for the hydrogenation of a wide variety of aromatic hydrocarbons and N-heteroaromatic compounds representative of components of petroleum-derived fuels. The experimental data indicate the existence of two distinct active sites in the nanostructure that lead to two parallel hydrogenation pathways, one for simple aromatics involving conventional homolytic hydrogen splitting on Ru and a second one for N-heteroaromatics taking place via a novel heterolytic hydrogen activation on the catalyst surface, assisted by the basic pyridine groups of the support.
Unsaturated Aldehydes as Alkene Equivalents in the Diels–Alder Reaction
作者:Esben Taarning、Robert Madsen
DOI:10.1002/chem.200800003
日期:2008.6.20
A one-pot procedure is described for using alpha,beta-unsaturated aldehydes as olefin equivalents in the Diels-Alder reaction. The method combines the normal electron demand cycloaddition with aldehyde dienophiles and the rhodium-catalyzed decarbonylation of aldehydes to afford cyclohexenes with no electron-withdrawing substituents. In this way, the aldehyde group serves as a traceless control element
The present invention provides a class of novel substituted bicyclooctanes which have pesticidal activity, particularly against arthropod pests. Pesticidal formulations containing the compounds of the formula (I), their use in the control of pests and methods for their preparation are also disclosed.
The reaction of cycloalkene with
iodineâcerium(IV) ammonium nitrate (CAN) in
acetonitrileâwater (10:1â1:1) affords the
corresponding trans-iodohydrins and
trans-iodonitrates; when
iodineâcerium(IV) sulfate (CS) in
acetonitrileâwater (10:1) at 50 °C is used,
trans-iodohydrins are obtained preferentially.