1462-03-9Relevant articles and documents
Deciphering Reactivity and Selectivity Patterns in Aliphatic C-H Bond Oxygenation of Cyclopentane and Cyclohexane Derivatives
Martin, Teo,Galeotti, Marco,Salamone, Michela,Liu, Fengjiao,Yu, Yanmin,Duan, Meng,Houk,Bietti, Massimo
supporting information, p. 9925 - 9937 (2021/06/30)
A kinetic, product, and computational study on the reactions of the cumyloxyl radical with monosubstituted cyclopentanes and cyclohexanes has been carried out. HAT rates, site-selectivities for C-H bond oxidation, and DFT computations provide quantitative information and theoretical models to explain the observed patterns. Cyclopentanes functionalize predominantly at C-1, and tertiary C-H bond activation barriers decrease on going from methyl- and tert-butylcyclopentane to phenylcyclopentane, in line with the computed C-H BDEs. With cyclohexanes, the relative importance of HAT from C-1 decreases on going from methyl- and phenylcyclohexane to ethyl-, isopropyl-, and tert-butylcyclohexane. Deactivation is also observed at C-2 with site-selectivity that progressively shifts to C-3 and C-4 with increasing substituent steric bulk. The site-selectivities observed in the corresponding oxidations promoted by ethyl(trifluoromethyl)dioxirane support this mechanistic picture. Comparison of these results with those obtained previously for C-H bond azidation and functionalizations promoted by the PINO radical of phenyl and tert-butylcyclohexane, together with new calculations, provides a mechanistic framework for understanding C-H bond functionalization of cycloalkanes. The nature of the HAT reagent, C-H bond strengths, and torsional effects are important determinants of site-selectivity, with the latter effects that play a major role in the reactions of oxygen-centered HAT reagents with monosubstituted cyclohexanes.
To Rebound or...Rebound? Evidence for the "alternative Rebound" mechanism in Ca'H Oxidations by the systems nonheme Mn Complex/H2O2/carboxylic acid
Ottenbacher, Roman V.,Bryliakova, Anna A.,Shashkov, Mikhail V.,Talsi, Evgenii P.,Bryliakov, Konstantin P.
, p. 5517 - 5524 (2021/05/31)
In this work, it has been shown that aliphatic Ca'H oxidations by bioinspired catalyst systems Mn aminopyridine complex/H2O2/carboxylic acid in acetonitrile afford predominantly a mixture of the corresponding alcohol and the ester. The alcohol/ester ratio is higher for catalysts bearing electron-donating groups at the aminopyridine core. Isotopic labeling studies witness that the oxygen atom of the alcohol originates from the H2O2molecule, while the ester oxygen comes exclusively from the acid. Oxidation of ethylbenzene in the presence of acetic acid affords enantiomerically enriched 1-phenylethanol and 1-phenyl acetate, with close enantioselectivities and the same sign of absolute chirality. Experimental data and density functional theory calculations provide evidence in favor of the rate-limiting benzylic H atom abstraction by the high-spin (S = 1) [LMnV(O)OAc]2+active species followed by competitive OH/OC(O)R rebound. This mechanism has been unprecedented for Ca'H oxidations catalyzed by bioinspired Mn complexes. The trends governing the alcohol/ester ratios have been rationalized in terms of steric properties of the catalyst, acid, and substrate. copy; 2021 American Chemical Society.
Diester acid protection structure monomer and preparation method thereof
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Paragraph 0076-0082; 0096-0102; 0106-0112; 0119-0125, (2020/01/03)
The invention relates to the field of optical materials and in particular to a diester acid protection structure monomer and a preparation method thereof. The diester acid protection structure monomeris used as a raw material of a photoresist required in integrated circuit manufacturing. Due to a diester long side chain, the photoresist has a better film-forming property; due to the fact that small-size and high-acid-sensitivity groups hung outside can improve the deprotection reaction efficiency in the photoetching process, the quality of a photoetched product is improved; and in addition, the diester acid protection structure monomer prepared through the process method has high yield and purity, and the performance of the photoresist is further guaranteed.
Controllable Intramolecular Unactivated C(sp3)-H Amination and Oxygenation of Carbamates
Guo, Qihang,Ren, Xiang,Lu, Zhan
supporting information, p. 880 - 884 (2019/05/16)
Dual catalyst-controlled intramolecular unactivated C(sp3)-H amination and oxygenation of carbamates merging visible-light photocatalysis and earth-abundant transition metal catalysis have been reported. Useful amino alcohol and diol derivatives could be selectively obtained from readily available tertiary alcohol derivatives. The possible mechanisms have been proposed via a 1,5-HAT process followed by Lewis acid-controlled cyclization. The nickel and zinc catalysts inhibit the formation of oxygenation and amination products, respectively. An interesting phenomenon of chirality transfer is also observed.
PROCESS FOR THE PREPARATION OF 1-METHYLCYCLOPENTANE DERIVATIVES
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, (2012/05/04)
Process for the preparation of 1-methylcyclopentene by thermal reaction of cyclohexanol or cyclohexene or mixtures of both compounds to give 1-methylcyclopentene, wherein the resulting by-products 3-methylcyclopentene and 4-methylcyclopentene (double-bond isomers of 1-methylcyclopentene) are returned to the reaction.
PROCESS FOR THE PREPARATION OF 1-METHYL-1-ALKOXYCYCLOPENTANES
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, (2012/05/04)
Process for the preparation of cyclopentane derivatives of the formula I in which R is a C1- to C10-alkyl group, which comprises reacting cyclohexanol or cyclohexene or mixtures of both compounds to give 1-methyl-1-cyclopentene (1st stage) and subsequently adding a C1- to C10-alkanol onto the double bond of the 1-methyl-1-cyclopentene (2nd stage).
Di(hydroxo)porphyrin GeIV complex/silica gel composite as visible light-assisted radical generator
Shiragami, Tsutomu,Shiraki, Ryuichi,Makise, Ryuichi,Matsumoto, Jin,Yasuda, Masahide
body text, p. 874 - 875 (2011/01/10)
A composite of di(hydroxo)germaniumporphyrin with silica gel was used as radical generator which oxidized MeOH to HCHO and hydrocarbons to alcohols in aqueous solution.
Stereoselective synthesis of δ-lactones from 5-oxoalkanals via one-pot sequential acetalization, tishchenko reaction, and lactonization by cooperative catalysis of samarium ion and mercaptan
Hsu,Fang
, p. 8573 - 8584 (2007/10/03)
By the synergistic catalysis of samarium ion and mercaptan, a series of 5-oxoalkanals was converted to (substituted) δ-lactones in efficient and stereoselective manners. This one-pot procedure comprises a sequence of acetalization, Tishchenko reaction and lactonization. The deliberative use of mercaptan, by comparison with alcohol, is advantageous to facilitate the catalytic cycle. The reaction mechanism and stereochemistry are proposed and supported by some experimental evidence. Such samarium ion/mercaptan cocatalyzed reactions show the feature of remote control, which is applicable to the asymmetric synthesis of optically active δ-lactones. This study also demonstrates the synthesis of two insect pheromones, (2S,5R)-2-methylhexanolide and (R)-hexadecanolide, as examples of a new protocol for asymmetric reduction of long-chain aliphatic ketones.
Hydrosilylation of 1-methylcyclopentene
Yarosh,Zhilitskaya,Yarosh,Albanov,Burnashova,Voronkov
, p. 1395 - 1397 (2007/10/03)
Hydrosilylation of 1-methylcyclopentene with chloromethylsilanes Me3-nSiHCln (n = 2, 3) yields dichloro(cyclopentylmethyl)methyl-and trichloro(cyclopentylmethyl)silanes, respectively. Chlorodimethylsilane (n = 1) adds to 1-methylcyclopentene to give a mixture of cis-and trans-chloro(methyl)(2-methylcyclopentyl)silanes, as well as chloro(cyclopentylmethyl)methylsilane. The hydrosilylation products were reacted with ethynylmagnesium bromide to prepare the corresponding ethynyl derivatives. Reaction of (cyclopentylmethyl)triethynylsilane with ethylmagnesium bromide and chlorotrimethylsilane gave (cyclopentylmethyl)tris(trimethylsilylethynyl)silane.
