Results 1 - 10 of 1819
Results 1 - 10 of 1819. Search took: 0.023 seconds
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[en] The results of studies dealing with mechanisms of hydro-, carbo- and cycloalumination of alkenes and alkynes catalyzed by zirconium complexes are generalized and systematized for the first time. Data about the structures of intermediates responsible for the formation of the target compounds are presented and the available data on the effect of the structure of organoaluminium compounds and the electronic and steric factors determining the catalytic activity of metal complexes in these reactions are considered in detail. Much attention is paid to studies of the influence of reaction conditions on the chemo-, regio- and stereoselectivity of the Zr-containing complex catalysts. The bibliography includes 217 references.
[en] Ring closing metathesis of acyclic trienes that can provide oxacycles or carbocycles has been investigated. It was found that a substituent on one of the alkene units determines the reaction course to provide either oxacycles or carbocyles exclusively irrespective of the ring size of the resulting compounds.
Graphical AbstractRing closing metathesis of acyclic trienes with Grubbs’ first generation (G-I) catalyst was found to be greately influenced by the presence of an alkyl substituent on one of the alkene units to provide either oxacycles or carbocyles exclusively irrespective of the ring size of the resulting compounds. .
[en] We have demonstrated that Pd nanocatalysts directly immobilized on unmodified iron oxide MNPs are active, chemoselective, and readily recyclable in the hydrogenation of olefins. The procedure for immobilizing Pd nanocatalysts is simple and straightforward. Overall, the olefin hydrogenation using Pd nanocatalysts provides a useful tool for organic synthesis. The use of metal nanoparticles as the catalysts has been attracting great attention as a useful strategy for improving the catalytic efficiency of heterogeneous catalysts in a wide range of synthetic transformations. Metal nanoparticles proved to be significantly more efficient than their bulk counterparts due to their large surface area. Recently, we reported the use of palladium nanoparticles entrapped in AlO(OH) matrix as the efficient racemization catalyst in the dynamic kinetic resolution of primary amines. Subsequently, we became interested in the development of more readily recoverable palladium nano-catalyst for practical applications
[en] The published data on the chemistry of intermolecular 1,3-dipolar cycloaddition of nitrile oxides to different types of alkene derivatives are systematised. Various aspects of stereo- and regiochemistry of this reaction are considered. The bibliography includes 182 references.
[en] A new synthetic approach to α-keto cyano-phosphorane ylides from olefins utilizing a novel xanthate reagent 6 has been developed. There are several advantages expected from this new approach e. g., easy preparation of 6 from commercial reagents in excellent yield, mild reaction conditions, good to excellent overall yields. Currently we are doing additional experiments to determine the scope and limitation of this new approach, and those results will be reported in due course. We have developed new synthetic approaches to α-keto cyanophosphorane ylides from readily available chemicals using specially designed new reagents to overcome such limitation. For example, α-keto cyanophosphorane ylides have been prepared from carbonyl compounds using a new Horner-Wadsworth-Emmons (HWE) reagent, from alkyl bromides using a new phenylsulfinyl reagent through alkylation-sulfoxide elimination sequence, and from alkyl halides using a new phenylsulfonyl reagent via sequential alkylation-reductive desulfonylation protocol
[en] An efficient synthesis of 3-halofurans by the intramolecular cyclization of 2-(1-alkynyl)-2-alken-1-ones with cupric halide has been developed. A broad range of 3-chloro- and 3-bromofuran derivatives could be obtained in the present method in moderate to good yields. The 3-halofuran derivatives are potential synthetic intermediates for amplification of molecular complexity