22339-21-5Relevant articles and documents
Synthesis of bimetallic Zr(Ti)-naphthalendicarboxylate MOFs and their properties as Lewis acid catalysis
Rasero-Almansa, Antonia M.,Iglesias, Marta,Sánchez, Félix
, p. 106790 - 106797 (2016/11/23)
Bimetallic Zr(Ti)-NDC based metal-organic frameworks (MOFs) have been prepared by incorporation of titanium(iv) into zirconium(iv)-NDC-MOFs (UiO family). The resulting materials maintain thermal (up to 500 °C), chemical and structural stability with respect to parent Zr-MOFs as can be deduced from XRD, N2 adsorption, FTIR and thermal analysis. The materials have been studied in Lewis acid catalyzed reactions, such as, domino Meerwein-Ponndorf-Verley (MPV) reduction-etherification of p-methoxybenzaldehyde with butanol, isomerization of α-pinene oxide and cyclization of citronellal.
Ring-opening of epoxides promoted by organomolybdenum complexes of the type [(η5-C5H4R)Mo(CO)2(η3-C3H5)] and [(η5-C5H5)Mo(CO)3(CH2R)]
Bruno, Sofia M.,Gomes, Ana C.,Abrantes, Marta,Valente, Anabela A.,Pillinger, Martyn,Gon?alves, Isabel S.
, p. 179 - 183 (2015/10/19)
The cyclopentadienyl molybdenum carbonyl complexes [(η5-C5H4R)Mo(CO)2(η3-C3H5)] and [(η5-C5H5)Mo(CO)3(CH2R)] (R = H, COOH) have been shown to promote acid-catalysed reactions in liquid phase, under moderate conditions. The catalytic alcoholysis of styrene oxide with ethanol at 35 °C gave 2-ethoxy-2-phenylethanol in 100% yield within 30 min for the dicarbonyl complexes and 3-6 h for the tricarbonyl complexes. Steady catalytic performances were observed in consecutive runs with the same catalytic solution, suggesting fairly good catalytic stability. In the second acid-catalysed reaction studied, the isomerization of α-pinene oxide at 55 °C gave campholenic aldehyde and trans-carveol in a total yield of up to 86% at 100% conversion. Chemoselectivity is shown to be solvent dependent.
Isomerization of bicyclic terpene epoxides into allylic alcohols without changing of the initial structure
Demidova, Yu.S.,Ardashov,Simakova,Simakova,Volcho,Salakhutdinov,Murzin, D.Yu.
, p. 162 - 166 (2014/06/09)
A novel method of (1S,2R,3R,5R)-6,6-dimethyl-4-methylenebicyclo[3.1.1] heptane-2,3-diol synthesis, which is a valuable intermediate in the synthesis of a perspective potent anti-Parkinson drugs, in the presence of TiO2 was proposed. Catalytic activity of TiO2 in the bicyclic terpene epoxides isomerization to corresponding allylic alcohols without changing of the initial structure was demonstrated, contrary to titania-supported Au catalysts which promoted rearrangement with predominant formation of a cyclopentene α-hydroxy ketone.
Isomerization of functionalized 2,3-epoxypinanes in the presence of Lewis acids
De Vialemaringe, Marianne,Bourgeois, Marie-Josephe,Monique Campagnole, Et,Montaudon, Evelyne
, p. 616 - 629 (2007/10/03)
The functionalized 2,3-epoxypinanes 1b-i were submitted to isomerization in the presence of ZnBr2 at 110°(Table 1) or of BF3 · Et2O at different temperatures (Table 2), and their behavior was compared with that of the non- functionalized parent 1a and with similar known transpositions. The produced campholenals 2, pinocamphones 3, and in some cases, fencholenals 4 were isolated and characterized. A mechanism involving a concerted oxirane ring opening is proposed (scheme 4).
Transition-Metal Catalyzed Autoxidation of cis- and trans-Pinane to a Mixture of Diastereoisomeric Pinanols
Sercheli, Ricardo,Ferreira, Alfredo L. B.,Baptistella, Lúcia H. B.,Schuchardt, Ulf
, p. 1361 - 1364 (2007/10/03)
Autoxidations of the pinanes, obtained after hydrogenation of naturally occurring Pinus elliottii oil, were performed with or without solvent, using the catalytic system Co(OAc)2/Mn(OAc)2/NH4Br in a 9:1:5 molar ratio, and dioxygen as the oxidant. The best selectivity for the pinanols was 71% (cis:trans ratio, 3:1) with 17% conversion. Autoxidations were also carried out in the absence of catalyst. The hydroperoxides formed with 17% conversion were decomposed with Na2SO3 and PPh3, resulting in 62% pinanols (cis:trans ratio, 5:1). The pyrolysis of the pinanols at 600°C and a contact time of 1.15 × 10-2 s/mol yielded 54% of linalool. The side products were mainly due to an "ene" reaction, giving diastereoisomeric 1,2-dimethyl-3-isopropenylcyclopentanols.
Aminium Salts Catalyzed Rearrangement of α-Pinene and β-Ionone Oxides
Lopez, Luigi,Mele, Giuseppe,Fiandanese, Vito,Cardellicchio, Cosimo,Nacci, Angelo
, p. 9097 - 9106 (2007/10/02)
β-ionone and α-pinene oxides 1,3 isomerize rapidly and selectively to 1-(1,2,2-trimethylcyclopent-1-yl)-pent-2-en-1,4-dione 2 and the industrially important 2,2,3-trimethyl-3-cyclopentene acetaldehyde 4, under the influence of catalytic amounts of aminium salts A, B.In order to find insights into the mechanism of our procedure, protic and Lewis acids-catalyzed rearrangements have also been reconsidered.
Studies on the Oxidation of cis- and trans-Pinane with Molecular Oxygen
Brose, Thomas,Pritzkow, Wilhelm,Thomas, Gerda
, p. 403 - 409 (2007/10/02)
The pinanes are preferably attacked at the tertiary C-H bond in 2-position, but products of the oxidative attack at the secondary C-H-bonds in 3- and 4-position are also found.At 100 deg C cis-pinane is attacked more easily than trans-pinane (kcis : ktrans = 6.4), the relative rates of attack at the secondary C-H bonds in positions 3 and 4 with respect to the tertiary C-H bond in 2-position were also determined (in cis-pinane ksec : ktert = 0.027; in trans-pinane ksec : ktert = 0.20).After the attack at the 2-C-H bond the radical formed can either react with oxygen to form the corresponding cis- and trans-peroxy radicals and further to give cis- and trans-2-hydroperoxy pinane or fragmentate to the monocyclic radical derived from α-terpinene, giving as a final products α-terpinene hydroperoxide and the bicyclic 8-hydroperoxy 4,4,8-trimethyl 2,3-dioxabicyclononane.The corresponding alcohols were found after reduction with sodium sulphite.The oxidation at position 2 of the pinanes delivers not only the cis- and trans-hydroperoxide but also, as short-lived intermediates, the corresponding 2-pinanyloxy radicals.These radicals fragmentate forming a carbon radical with cyclobutane structure whose oxidation products were identified.Besides fragmentation of the 2-pinanyloxy radical also an intramolecular H-transfer from the methyl group in 9-position to the oxygen of the trans-pinanyloxy radical takes place leading to 9-hydroperoxy trans-pinane-2-ol.
ORGANOBORANES FOR SYNTHESIS. 3. OXIDATION OF ORGANOBORANES WITH AQUEOUS CHROMIC ACID. A CONVENIENT SYNTHESIS OF KETONES FROM ALKENES VIA HYDROBORATION
Brown, Herbert C.,Garg, Chandra P.
, p. 5511 - 5514 (2007/10/02)
Organoboranes react with alkaline hydrogen peroxide to provide a wide variety of alcohols.These alcohols can be taken up in ether solvent and converted without isolation into the corresponding ketones by treatment with chromic acid.Organoboranes can also be oxidized directly with chromic acid to the corresponding ketones.The chromic acid oxidation of organoboranes provides a new, convenient procedure for the synthesis of α-substituted cycloalkanones via hydroboration.The conversion of organoboranes into ketones proceeds through the intermediate alcohol.Representative cycloalkanones and α-methylcycloalkanones have been prepared from the corresponding alkenes via hydroboration, followed by chromic acid oxidation.
