1197-07-5Relevant articles and documents
Arbuzov,B.A. et al.
, (1965)
Isomerization of α-pinene oxide using Fe-supported catalysts: Selective synthesis of campholenic aldehyde
Stekrova, Martina,Kumar, Narendra,Aho, Atte,Sinev, Ilia,Grünert, Wolfgang,Dahl, Johnny,Roine, Jorma,Arzumanov, Sergey S.,M?ki-Arvela, P?ivi,Murzin, Dmitry Yu.
, p. 162 - 176 (2014)
α-Pinene oxide, an oxygenated derivative of α-pinene, can be converted into various valuable substances useful as flavour, fragrance and pharmaceutical compounds. Campholenic aldehyde is one of the most desired products of α-pinene oxide isomerization being a valuable intermediate for the production of sandalwood-like fragrances. Iron modified zeolites Beta-75 and ZSM-5, mesoporous material MCM-41, silica and alumina were prepared by two methods (impregnation and solid-state ion exchange) and tested for selective preparation of campholenic aldehyde by isomerization of α-pinene oxide. The characterization of tested catalyst was carried out using scanning electron microscope analysis, nitrogen adsorption measurements, pyridine adsorption-desorption with FTIR, X-ray absorption spectroscopy measurements, XPS-analysis, 29Si MAS NMR and 27Al MAS NMR and X-ray diffraction. The isomerization of α-pinene oxide was carried out in toluene as a solvent at 70 C. The main properties influencing the activity and the selectivity are the acidic and structural properties of the tested catalysts. The highest selectivity of 66% was achieved at complete conversion of α-pinene oxide with Fe-MCM-41.
Tailoring Lewis/Br?nsted acid properties of MOF nodesviahydrothermal and solvothermal synthesis: simple approach with exceptional catalytic implications
Bohigues, Benjamin,Boronat, Mercedes,Corma, Avelino,Lopes, Christian W.,Meira, Débora M.,Moliner, Manuel,Rojas-Buzo, Sergio
, p. 10106 - 10115 (2021)
The Lewis/Br?nsted catalytic properties of the Metal-Organic Framework (MOF) nodes can be tuned by simply controlling the solvent employed in the synthetic procedure. In this work, we demonstrate that Hf-MOF-808 can be prepared from a material with a higher amount of Br?nsted acid sites,viamodulated hydrothermal synthesis, to a material with a higher proportion of unsaturated Hf Lewis acid sites,viamodulated solvothermal synthesis. The Lewis/Br?nsted acid properties of the resultant metallic clusters have been studied by different characterization techniques, including XAS, FTIR and NMR spectroscopies, combined with a DFT study. The different nature of the Hf-MOF-808 materials allows their application as selective catalysts in different target reactions requiring Lewis, Br?nsted or Lewis-Br?nsted acid pairs.
Heteropoly acid catalysts in upgrading of biorenewables: Synthesis of para-menthenic fragrance compounds from α-pinene oxide
Ribeiro, Cláudio J.A.,Pereira, Matheus M.,Kozhevnikova, Elena F.,Kozhevnikov, Ivan V.,Gusevskaya, Elena V.,da Silva Rocha, Kelly A.
, p. 166 - 170 (2020)
The isomerization of α-pinene oxide in the presence of Cs2.5H0.5PW12O40 (CsPW) heteropolysalt as solid acid catalyst is reported. The reactions were performed in various solvents, which allowed to obtain trans-carveol, trans-sobrerol and pinol in 60–80% yield each, which exceed the yields reported so far. The CsPW catalyst could be recovered and reused without loss of its activity and selectivity.
Photocontrolled Cobalt Catalysis for Selective Hydroboration of α,β-Unsaturated Ketones
Beltran, Frédéric,Bergamaschi, Enrico,Funes-Ardoiz, Ignacio,Teskey, Christopher J.
supporting information, p. 21176 - 21182 (2020/09/17)
Selectivity between 1,2 and 1,4 addition of a nucleophile to an α,β-unsaturated carbonyl compound has classically been modified by the addition of stoichiometric additives to the substrate or reagent to increase their “hard” or “soft” character. Here, we demonstrate a conceptually distinct approach that instead relies on controlling the coordination sphere of a catalyst with visible light. In this way, we bias the reaction down two divergent pathways, giving contrasting products in the catalytic hydroboration of α,β-unsaturated ketones. This includes direct access to previously elusive cyclic enolborates, via 1,4-selective hydroboration, providing a straightforward and stereoselective route to rare syn-aldol products in one-pot. DFT calculations and mechanistic experiments confirm two different mechanisms are operative, underpinning this unusual photocontrolled selectivity switch.
