- METHOD OF PREPARING SILANOLS WITH SELECTIVE CYTOCHROME P450 VARIANTS AND RELATED COMPOUNDS AND COMPOSITIONS
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This disclosure provides a method of preparing a silanol-functional organosilicon compound with a cytochrome P450 variant that facilitates the oxidization of a silyl hydride group to a silanol group in the presence of oxygen. The method includes combining the cytochrome P450 variant and an organosilicon compound having at least one silicon-bonded hydrogen atom to give a reaction mixture and exposing the reaction mixture to oxygen to oxidize the organosilicon compound, thereby preparing the silanol-functional organosilicon compound. Cytochrome P450 variants suitable for use in the method are also disclosed, along with methods for engineering and optimizing the same. Nucleic acids encoding the cytochrome P450 variants and compositions, expression vectors, and host cells including the same are also disclosed.
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Paragraph 00122-00123
(2021/08/27)
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- Metal-free hydrogen evolution cross-coupling enabled by synergistic photoredox and polarity reversal catalysis
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A synergistic combination of photoredox and polarity reversal catalysis enabled a hydrogen evolution cross-coupling of silanes with H2O, alcohols, phenols, and silanols, which afforded the corresponding silanols, monosilyl ethers, and disilyl ethers, respectively, in moderate to excellent yields. The dehydrogenative cross-coupling of Si-H and O-H proceeded smoothly with broad substrate scope and good functional group compatibility in the presence of only an organophotocatalyst 4-CzIPN and a thiol HAT catalyst, without the requirement of any metals, external oxidants and proton reductants, which is distinct from the previously reported photocatalytic hydrogen evolution cross-coupling reactions where a proton reduction cocatalyst such as a cobalt complex is generally required. Mechanistically, a silyl cation intermediate is generated to facilitate the cross-coupling reaction, which therefore represents an unprecedented approach for the generation of silyl cationviavisible-light photoredox catalysis.
- Cao, Jilei,Lu, Kanghui,Ma, Lishuang,Yang, Xiaona,Zhou, Rong
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supporting information
p. 8988 - 8994
(2021/11/23)
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- Selective Enzymatic Oxidation of Silanes to Silanols
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Compared to the biological world's rich chemistry for functionalizing carbon, enzymatic transformations of the heavier homologue silicon are rare. We report that a wild-type cytochrome P450 monooxygenase (P450BM3 from Bacillus megaterium, CYP102A1) has promiscuous activity for oxidation of hydrosilanes to give silanols. Directed evolution was applied to enhance this non-native activity and create a highly efficient catalyst for selective silane oxidation under mild conditions with oxygen as the terminal oxidant. The evolved enzyme leaves C?H bonds present in the silane substrates untouched, and this biotransformation does not lead to disiloxane formation, a common problem in silanol syntheses. Computational studies reveal that catalysis proceeds through hydrogen atom abstraction followed by radical rebound, as observed in the native C?H hydroxylation mechanism of the P450 enzyme. This enzymatic silane oxidation extends nature's impressive catalytic repertoire.
- Arnold, Frances H.,B?hr, Susanne,Brinkmann-Chen, Sabine,Garcia-Borràs, Marc,Houk, K. N.,Katsoulis, Dimitris E.,Roberts, John M.
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supporting information
p. 15507 - 15511
(2020/05/05)
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- A method for catalytic synthesis of silanol
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The invention discloses a method for catalytically synthesizing silanol and relates to the fields of organic chemicals and fine chemicals. The method is essentially a transition metal catalyzed organic synthesis reaction. In the method, the raw materials comprise organosilane and a clean oxidant, a used catalyst is inexpensive copper salt, the raw material is heated and stirred to react without a solvent so as to rapidly produce silanol at a moderate temperature. By adopting the method, the reaction time is 3-12 hours. The mole ratio of the organosilane to the clean oxidant is 1:(1-5), the copper salt as the catalyst accounts for 1-10mol% of the mole number of the organosilane, the raw materials react at a temperature of 50-80 DEG C, and then the silanol can be greatly yielded after simple posttreatment. The oxidant used in the method is safe and nontoxic, and the catalyst used in the method is cheap and easily available. The method disclosed by the invention is a very simple and practical method for synthesizing silanol.
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Paragraph 0018; 0051; 0052
(2017/07/12)
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- Organocatalytic oxidation of organosilanes to silanols
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The oxidation of organosilanes to silanols constitutes an attractive transformation for both industry and academia. Bypassing the need for stoichiometric oxidants or precious metal catalytic complexes, the first organocatalytic oxidation of silanes has been accomplished. Catalytic amounts of 2,2,2-trifluoroacetophenone, in combination with the green oxidant H 2O2, lead to excellent to quantitative yields in a short reaction time. A variety of alkyl, aryl, alkenyl, and alkynyl substituents can be tolerated, providing an easy, cheap, efficient, and practical solution to a highly desirable transformation.
- Limnios, Dimitris,Kokotos, Christoforos G.
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p. 2239 - 2243
(2013/10/22)
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- Diorganotelluride-catalyzed oxidation of silanes to silanols under atmospheric oxygen
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Diorganotellurides efficiently catalyze the aerobic oxidation of organosilanes under photosensitized conditions to afford the corresponding silanols in excellent yield.
- Okada, Yasunori,Oba, Makoto,Arai, Atsushi,Tanaka, Kazuhito,Nishiyama, Kozaburo,Ando, Wataru
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scheme or table
p. 383 - 385
(2010/04/28)
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- A novel method for preparing silanols from silylmethanols
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Various types of silylmethanols were converted into their corresponding silanols in good to excellent yield under mild oxidation conditions using TEMPO (2,2,6,6-tetramethyl-l-piperidinyloxyl). Copyright
- Takeda, Daisuke,Oyama, Ryo,Yamada, Shozo
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supporting information; experimental part
p. 532 - 533
(2011/04/22)
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- Palladium-catalyzed cross-coupling of five-membered heterocyclic silanolates
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(Chemical Equation Presented) The preparation of π-rich 2-aryl heterocycles by palladium-catalyzed cross-coupling of sodium heteroarylsilanolates with aryl iodides, bromides, and chlorides is described. The cross-coupling process was developed through extensive optimization of the following key variables: (1) identification of stable, isolable alkali metal silanolates, (2) identification of conditions for preformation and isolation of silanolate salts, (3) judicious choice in the palladium catalyst/ligand combination, and (4) selection of the protecting group on the nitrogen of indole. It was found that the alkali metal silanolates, either isolated or formed in situ, offered a significant rate enhancement and broader substrate scope over the use of silanols activated by Bronsted bases such as NaOt-Bu. In addition, the optimized conditions for the cross-coupling of 2-indolylsilanolates were readily applied to the cross-coupling of 2-pyrrolyl-, 2-furyl-, and 2-thienylsilanolates.
- Denmark, Scott E.,Baird, John D.,Regens, Christopher S.
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p. 1440 - 1455
(2008/04/12)
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- Palladium-catalyzed cross-coupling reactions of heterocyclic silanolates with substituted aryl iodides and bromides
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Sodium silanolates derived from a number of heterocyclic silanols undergo cross-coupling with a variety of aromatic iodides and bromides under mild conditions. In situ deprotonation of the silanols with an equivalent amount of sodium hydride in toluene ge
- Denmark, Scott E.,Baird, John D.
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p. 793 - 795
(2007/10/03)
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- Highly Efficient Iridium-Catalyzed Oxidation of Organosilanes to Silanols
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Hydrolytic oxidation of organosilanes to the corresponding silanols can be performed highly efficiently with a catalyst system of [IrCl(C8H 12)]2 under essentially neutral and mild conditions, and various types of silanols are produced in good to excellent yields.
- Lee, Youngjun,Seomoon, Dong,Kim, Sundae,Han, Hoon,Chang, Sukbok,Lee, Phil Ho
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p. 1741 - 1743
(2007/10/03)
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