51652-47-2Relevant articles and documents
Pheromones. XXXVII. Stereospecific synthesis of the sex pheromone of Antherea polyphemus: (6(E),11(Z)-hexadecadienyl acetate and 6(E),11(Z)-hexadecadienal
Bestmann,Li
, p. 4941 - 4944 (1981)
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INSECT PHEROMONES AND THEIR ANALOGUES XXXI. SYNTHESIS OF DEC-5Z-EN-1-YL ACETATE AND HENEICOS-6Z-EN-11-ONE FROM A FUNCTIONALLY DIFFERENTIATED PRODUCT OF THE OZONOLYSIS OF CYCLOPENTENE
Odinokov, V. N.,Akhmetova, V. R.,Khasanov, Kh. D.,Abduvakhabov, A. A.,Tolstikov, O. A.
, p. 497 - 499 (1991)
Dec-5Z-en-1-yl acetate and heneicos-6Z-en-11-one - pheromones of insects of the genera Agrotis and Orgyia, respectively - have been synthesized from a product of the functionally differentiated ozonolysis of cyclopentene.
An Amine-Assisted Ionic Monohydride Mechanism Enables Selective Alkyne cis-Semihydrogenation with Ethanol: From Elementary Steps to Catalysis
Huang, Zhidao,Wang, Yulei,Leng, Xuebing,Huang, Zheng
supporting information, p. 4824 - 4836 (2021/04/07)
The selective synthesis of Z-alkenes in alkyne semihydrogenation relies on the reactivity difference of the catalysts toward the starting materials and the products. Here we report Z-selective semihydrogenation of alkynes with ethanol via a coordination-induced ionic monohydride mechanism. The EtOH-coordination-driven Cl- dissociation in a pincer Ir(III) hydridochloride complex (NCP)IrHCl (1) forms a cationic monohydride, [(NCP)IrH(EtOH)]+Cl-, that reacts selectively with alkynes over the corresponding Z-alkenes, thereby overcoming competing thermodynamically dominant alkene Z-E isomerization and overreduction. The challenge for establishing a catalytic cycle, however, lies in the alcoholysis step; the reaction of the alkyne insertion product (NCP)IrCl(vinyl) with EtOH does occur, but very slowly. Surprisingly, the alcoholysis does not proceed via direct protonolysis of the Ir-C(vinyl) bond. Instead, mechanistic data are consistent with an anion-involved alcoholysis pathway involving ionization of (NCP)IrCl(vinyl) via EtOH-for-Cl substitution and reversible protonation of Cl- ion with an Ir(III)-bound EtOH, followed by β-H elimination of the ethoxy ligand and C(vinyl)-H reductive elimination. The use of an amine is key to the monohydride mechanism by promoting the alcoholysis. The 1-amine-EtOH catalytic system exhibits an unprecedented level of substrate scope, generality, and compatibility, as demonstrated by Z-selective reduction of all alkyne classes, including challenging enynes and complex polyfunctionalized molecules. Comparison with a cationic monohydride complex bearing a noncoordinating BArF- ion elucidates the beneficial role of the Cl- ion in controlling the stereoselectivity, and comparison between 1-amine-EtOH and 1-NaOtBu-EtOH underscores the fact that this base variable, albeit in catalytic amounts, leads to different mechanisms and consequently different stereoselectivity.
Stereoselective Alkyne Hydrogenation by using a Simple Iron Catalyst
Gregori, Bernhard J.,Schwarzhuber, Felix,P?llath, Simon,Zweck, Josef,Fritsch, Lorena,Schoch, Roland,Bauer, Matthias,Jacobi von Wangelin, Axel
, p. 3864 - 3870 (2019/07/31)
The stereoselective hydrogenation of alkynes constitutes one of the key approaches for the construction of stereodefined alkenes. The majority of conventional methods utilize noble and toxic metal catalysts. This study concerns a simple catalyst comprised of the commercial chemicals iron(II) acetylacetonate and diisobutylaluminum hydride, which enables the Z-selective semihydrogenation of alkynes under near ambient conditions (1–3 bar H2, 30 °C, 5 mol % [Fe]). Neither an elaborate catalyst preparation nor addition of ligands is required. Mechanistic studies (kinetic poisoning, X-ray absorption spectroscopy, TEM) strongly indicate the operation of small iron clusters and particle catalysts.
Facile Light-Mediated Preparation of Small Polymer-Coated Palladium-Nanoparticles and Their Application as Catalysts for Alkyne Semi-Hydrogenation
M?sing, Florian,Wang, Xi,Nüsse, Harald,Klingauf, Jürgen,Studer, Armido
supporting information, p. 6014 - 6018 (2017/05/05)
A facile light-mediated preparation of small palladium nanoparticles (PdNPs) with a diameter of 1.3 nm and low dispersity by using low-priced and readily prepared photoactive polymers is presented. These polymers act as reagents for the photochemical reduction of Pd ions and they are also stabilizers for the PdNPs generated in situ. The PdNP–polymer hybrid materials prepared by this reliable approach are efficient hydrogenation catalysts that show high activity and Z-selectivity in the semi-hydrogenation of alkynes. These PdNP–catalyst hybrid materials can be readily recycled and reused up to five times.
