13807-91-5Relevant academic research and scientific papers
Electron-transfer reduction of selected alcohols with alkalide K-, K+(15-crown-5)2 via organometallic intermediates
Grobelny, Zbigniew,Stolarzewicz, Andrzej,Maercker, Adalbert,Krompiec, Stanis,Kasperczyk, Janusz,Rzepa, Józef,Frey, Holger
, p. 2361 - 2367 (2004)
The course of the reaction of alkalide K-, K+ (15-crown-5)2 1 with selected alcohols depends on the kind of alcohol and the mode of substrate delivery. In the case of methanol, potassium methoxide formed initially undergoes destructfion at the excess of 1. It results in potassium oxide and methylpotassium. The latter opens the crown ether ring giving potassium tetraethylene glycoxide vinyl ether and methane. A similar course of the process is observed for propanol. Potassium glycidoxide is the main product formed in the reaction of 1 with glycidol. Its oxirane ring is opened at the excess of 1. Organopotassium alkoxides, i.e., potassium potassiomethoxide and dipotassium potassiopropane-1,2-dioxide are intermediate products of this reaction. They react then with the crown ether. Potassium methoxide, potassium enolate of acetaldehyde, dipotassium propane-1, 2-dioxide and potassium tetraethylene glycoxide vinyl ether are the final products of this process.
A Chiral Copper Catalyzed Site-Selective O-Alkylation of Carbohydrates
Ren, Bo,Wang, Jiaxi,Zhang, Mengyao,Chen, Yue,Zhao, Wei
supporting information, p. 665 - 670 (2021/12/02)
Highly regioselective alkylation of sugar hydroxyl groups has always been an important challenge in carbohydrate chemistry, especially for the selective alkylation of trans diols, there is no direct and efficient catalytic method so far. A chiral copper c
Hydrogen bonding-catalysed alcoholysis of propylene oxide at room temperature
Li, Ruipeng,Liu, Zhimin,Wang, Yuepeng,Xiang, Junfeng,Xu, Yueting,Zhang, Fengtao,Zhao, Yanfei
supporting information, p. 8734 - 8737 (2021/09/08)
Alcoholysis of propylene oxide (PO) is achieved over azolate ionic liquids (IL,e.g., 1-hydroxyethyl-3-methyl imidazolium imidazolate) at room temperature, accessing glycol ethers in high yields with excellent selectivity (e.g., >99%). Mechanism investigation indicates that cooperation of hydrogen-bonding of the anion with methanol and that of the cation with PO catalyses the reaction.
Benzoxaborole Catalyst for Site-Selective Modification of Polyols
Kusano, Shuhei,Miyamoto, Shoto,Matsuoka, Aki,Yamada, Yuji,Ishikawa, Ryuta,Hayashida, Osamu
supporting information, p. 1598 - 1602 (2020/02/11)
The site-selective modification of polyols bearing several hydroxyl groups without the use of protecting groups remains a significant challenge in synthetic chemistry. To address this problem, novel benzoxaborole derivatives were designed as efficient catalysts for the highly site-selective and protecting-group-free modification of polyols. To identify the effective substituent groups enhancing the catalytic activity and selectivity, a series of benzoxaborole catalysts 1a–k were synthesized. In-depth analysis for the substituent effect revealed that 1i–k, bearing multiple electron-withdrawing fluoro- and trifluoromethyl groups, exhibited the greatest catalytic activity and selectivity. Moreover, 1i-catalyzed benzoylation, tosylation, benzylation, and glycosylation of various cis-1,2-diol derivatives proceeded with good yield and site-selective manner.
Regio/site-selective alkylation of substrates containing a: Cis -, 1,2- or 1,3-diol with ferric chloride and dipivaloylmethane as the catalytic system
Lv, Jian,Liu, Yu,Zhu, Jia-Jia,Zou, Dapeng,Dong, Hai
supporting information, p. 1139 - 1144 (2020/03/11)
In this study, we reported the regio/site-selective alkylation of substrates containing a cis-, 1,2- or 1,3-diol with FeCl3 as a key catalyst. A catalytic system consisting of FeCl3 (0.01-0.1 equiv.) and dipivaloylmethane (FeCl3/dipivaloylmethane = 1/2) was used to catalyze the alkylation in the presence of a base. The produced selectivities and isolated yields were similar to those obtained by methods using the same amount of FeL3 (L = acylacetone ligand) as the catalyst in most cases. The previously reported FeL3 catalysts for alkylation are not commercially available and have to be synthesized prior to use. In contrast, FeCl3 and dipivaloylmethane (Hdipm) are very common and inexpensive nontoxic reagents in the lab, thereby making the method much greener and easier to handle. Mechanism studies confirmed for the first time that FeCl3 initially reacts with two equivalents of Hdipm to form [Fe(dipm)3] in the presence of a base in acetonitrile, followed by the formation of a five or six-membered ring intermediate between [Fe(dipm)3] and two hydroxyl groups of the substrate. A subsequent reaction between the cyclic intermediate and the alkylating agent results in selective alkylation of the substrate.
Ruthenium-Catalyzed Selective Hydrogenation of Epoxides to Secondary Alcohols
Thiyagarajan, Subramanian,Gunanathan, Chidambaram
supporting information, p. 9774 - 9778 (2019/12/02)
A ruthenium(II)-catalyzed highly selective Markovnikov hydrogenation of terminal epoxides to secondary alcohols is reported. Diverse substitutions on the aryl ring of styrene oxides are tolerated. Benzylic, glycidyl, and aliphatic epoxides as well as diepoxides also underwent facile hydrogenation to provide secondary alcohols with exclusive selectivity. Metal-ligand cooperation-mediated ruthenium trans-dihydride formation and its reaction involving oxygen and the less substituted terminal carbon of the epoxide is envisaged for the origin of the observed selectivity.
IRAK DEGRADERS AND USES THEREOF
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Paragraph 2284; 2285, (2019/07/10)
The present invention provides compounds, compositions thereof, and methods of using the same.
Double-hetero atom six-membered ring of synthetic method
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Paragraph 0110; 0111; 0112; 0113, (2018/07/30)
The invention provides a double-hetero atom six-membered ring of synthetic method. The synthetic method comprises to alkyl substituted cyclopropane and benzyl alcohol and/or a the oxygen radical animal pen is mellow as the starting material, sequentially carry out the ring-opening reaction, a transesterification reaction, 1st sulfonylation reaction, alcoholysis reaction and the nucleophilic substitution reaction, catalytic hydrogenation reaction and 2nd sulfonylation reaction and forming ring reaction, to obtain the required double-hetero atom six-membered ring, a formula (1) of the structure shown. In order to price the comparatively cheap racemic alkyl substituted cyclopropane as raw materials, to participate in the ring-opening reaction, to obtain a ring opening product. Then under the action of the esterase, make the ring-opening products which is a transesterification reaction, disposable obtain the desired racemic compound. This avoids the traditional method of multi-step separation and purification in the synthesis step, shortens the synthetic route. In the above synthetic route also avoids the need to use some dangerous reagent, process more security, reducing waste generation, and save the process cost.
Piers' borane-mediated hydrosilylation of epoxides and cyclic ethers
Zhang, Jianbo,Park, Sehoon,Chang, Sukbok
supporting information, p. 7243 - 7246 (2018/07/05)
We report the first diarylborane-catalysed hydrosilylation of epoxides and cyclic ethers. Mechanistic studies on the in situ generated Piers' borane (C6F5)2BH with hydrosilanes in the presence of an epoxide revealed that an alkyloxy(diaryl)borane (C6F5)2BOR is readily formed as a catalytically competent species for the outer-sphere hydrosilylation of epoxides and cyclic ethers.
Regioselective alkylation of carbohydrates and diols: A cheaper iron catalyst, new applications and mechanism
Ren, Bo,Yan, Ningning,Gan, Lu
, p. 46257 - 46262 (2017/10/11)
As an extension of our previous research on the regioselective protection of carbohydrates and diols, we developed an iron catalyst, Fe(dibm)3 (dibm = diisobutyrylmethane), which has an unusually broad catalytic scope in the selective monoalkyl
