13043-55-5Relevant articles and documents
Synthesis of methyl Β-alkylcarboxylates by Pd/diphosphine-catalyzed methoxycarbonylation of methylenealkanes RCH2CH2C(R)=CH2
Nifant'ev, Ilya E.,Sevostyanova, Nadezhda T.,Batashev, Sergey A.,Vinogradov, Alexey A.,Vinogradov, Alexander A.,Churakov, Andrei V.,Ivchenko, Pavel V.
, p. 123 - 132 (2019)
A series of methylenealkanes RCH2CH2(R)C = CH2 (R = n-butyl, n-hexyl, isopropyl and isobutyl), which are products of selective zirconocene-catalyzed dimerization of α-olefins, were introduced into Pd-catalyzed methoxycarbonylation. With the use of 5-methyleneundecane (1-hexene dimer) as a substrate, the roles of protic acid, Lewis acid and molecular hydrogen were established for model Pd(II)/PPh3 and Pd(II)/diphosphine catalysts. A series of bridged diphosphines were studied as catalyst components L in PdCl2/L-catalyzed methoxycarbonylation in the presence of H2. One of the nine diphosphines studied, trans-2,3-bis(diphenylphosphinomethyl)norbornane, demonstrated the best catalytic results in terms of catalytic activity, selectivity and isolated yields of the products. Under the optimized conditions during 24 h experiments, dimers RCH2CH2(R)C = CH2 were transformed to methyl carboxylates RCH2CH2(R)CHCH2COOMe with 99+% regioselectivity; isolated yields were 62–81%. In that way, the catalytic methoxycarbonylation of synthetically available methylenealkanes is an effective approach to branched carboxylic acids, with high prospects for practical application.
Highly Efficient and 1,2-Regioselective Method for the Oligomerization of 1-Hexene Promoted by Zirconium Precatalysts with [OSSO]-Type Bis(phenolate) Ligands
Nakata, Norio,Nakamura, Kazuaki,Ishii, Akihiko
, p. 2640 - 2644 (2018)
A mixture of zirconium complex 7, which carries a phenyl-substituted [OSSO]-type bis(phenolate) ligand, and dried modified methylaluminoxane (dMMAO) catalyzes the 1,2-regioselective oligomerization of 1-hexene at relatively low catalyst loadings (0.0056 mol %) to produce the corresponding vinylidene-terminated dimer, 5-methyleneundecane (74-80%), and trimer, 7-butyl-5-methylenetridecane (8-11%). The observed turnover frequencies (TOFs) are relatively high (up to 11a€?100 h-1). When a mixture of 2,6-dimethylphenyl-substituted precatalyst 8 and dMMAO was used, the oligomerization of 1-hexene proceeded effectively to afford predominantly the dimer (87-91%) together with a small amount of the trimer (8-11%) at remarkably high TOFs (up to 6640 h-1).
Oxidative Cleavage of Alkenes by O2with a Non-Heme Manganese Catalyst
Bennett, Elliot L.,Brookfield, Adam,Guan, Renpeng,Huang, Zhiliang,Mcinnes, Eric J. L.,Robertson, Craig M.,Shanmugam, Muralidharan,Xiao, Jianliang
supporting information, p. 10005 - 10013 (2021/07/19)
The oxidative cleavage of C═C double bonds with molecular oxygen to produce carbonyl compounds is an important transformation in chemical and pharmaceutical synthesis. In nature, enzymes containing the first-row transition metals, particularly heme and non-heme iron-dependent enzymes, readily activate O2 and oxidatively cleave C═C bonds with exquisite precision under ambient conditions. The reaction remains challenging for synthetic chemists, however. There are only a small number of known synthetic metal catalysts that allow for the oxidative cleavage of alkenes at an atmospheric pressure of O2, with very few known to catalyze the cleavage of nonactivated alkenes. In this work, we describe a light-driven, Mn-catalyzed protocol for the selective oxidation of alkenes to carbonyls under 1 atm of O2. For the first time, aromatic as well as various nonactivated aliphatic alkenes could be oxidized to afford ketones and aldehydes under clean, mild conditions with a first row, biorelevant metal catalyst. Moreover, the protocol shows a very good functional group tolerance. Mechanistic investigation suggests that Mn-oxo species, including an asymmetric, mixed-valent bis(μ-oxo)-Mn(III,IV) complex, are involved in the oxidation, and the solvent methanol participates in O2 activation that leads to the formation of the oxo species.
Diastereoselective synthesis of functionally substituted alkene dimers and oligomers, catalysed by chiral zirconocenes
Kovyazin, Pavel V.,Abdullin, Il'giz N.,Parfenova, Lyudmila V.
, p. 144 - 152 (2018/11/21)
The research addresses the reaction of terminal alkenes and propene with AlR3 (R = Me, Et) in the presence of chiral Zr complexes, rac-[Y(η5-C9H10)2]ZrCl2 (Y = C2H4, SiMe2) or (NMI)2ZrCl2 (NMI- η5–neomenthylindenyl), and methylaluminoxane. The effect of reaction conditions, catalyst and trialkylalane structure on the substrate conversion and the reaction chemo- and stereoselectivity has been studied. The reaction predominantly goes via the stage of alkene methyl(ethyl)zirconation with subsequent introduction of substrate molecules into the Zr-C bond. As a result, a diastereoselective one-pot method for the synthesis of functionally substituted linear terminal alkene dimers and propene oligomers was developed.
