- Silicon center chiral tetra-substituted silane and preparation method thereof
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The invention belongs to the field of organic synthesis, and discloses silicon center chiral tetra-substituted silane which has a structure shown as a general formula I. The invention also discloses apreparation method of the silicon center chiral tetra-substituted silane. Substrates dihydrosilane and olefin used in the method are economical and easy to obtain, and various silicon center chiral tetra-substituted silanes are constructed in one step with good yield and excellent enantioselectivity.
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Paragraph 0172-0178; 0183-0184
(2020/10/20)
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- Silicon center chiral dihydrobenzosilole and preparation method thereof
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The invention belongs to the field of organic synthesis, and discloses a silicon center chiral dihydrobenzosilole compound, which has a structure as shown in a general formula I. In the formula I, R1and R2 are independently selected from alkyl, phenyl, cyclopropyl methyl or phenoxyethyl, or R1 and R2 are formed, or R3 is selected from phenyl, benzyl, thienyl, naphthyl, benzofuran, Nmethylindole,morpholine or trimethylsilyl substituted phenyl; R4 is selected from phenyl, substituted phenyl, methoxy substituted pyridine, cyclohexyloxy, PhMe2Si, (EtO)3Si, triethyl germanium and pinacol boron, or R5 is selected from halogen, alkoxy or benzene ring, and the benzene ring and the connected benzene ring are condensed into naphthalene. The invention also provides a synthesis method of the compound. The product and the method provided by the invention can be widely applied to synthetic chemistry, medicinal chemistry and material science.
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Paragraph 0098; 0100-0104; 0107-0108
(2021/01/04)
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- Calcium Carbide Looping System for Acetaldehyde Manufacturing from Virtually any Carbon Source
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A vinylation/devinylation looping system for acetaldehyde manufacturing was evaluated. Vinylation of iso-butanol with calcium carbide under solvent-free conditions was combined with hydrolysis of the resulting iso-butyl vinyl ether under slightly acidic conditions. Acetaldehyde produced by hydrolysis was collected from the reaction mixture by simple distillation, and the remaining alcohol was redirected to the vinylation step. All the inorganic co-reagents can be looped as well, and the full sequence is totally sustainable. A complete acetaldehyde manufacturing cycle was proposed on the basis of the developed procedure. The cycle was fed with calcium carbide and produced the aldehyde as a single product in a total preparative yield of 97 %. No solvents, hydrocarbons, or metal catalysts were needed to maintain the cycle. As calcium carbide in principle can be synthesized from virtually any source of carbon, the developed technology represents an excellent example of biomass and waste conversion into a valuable industrial product.
- Rodygin, Konstantin S.,Lotsman, Kristina A.,Ananikov, Valentine P.
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p. 3679 - 3685
(2020/06/17)
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- Streamlined Construction of Silicon-Stereogenic Silanes by Tandem Enantioselective Ca'H Silylation/Alkene Hydrosilylation
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A rhodium-catalyzed tandem enantioselective Ca'H silylation/alkene hydrosilylation of dihydrosilanes, which enables the streamlined construction of a wide range of silicon-stereogenic silanes, is successfully developed. This process involves a SiH2-steered highly enantioselective Ca'H silylation to furnish the corresponding desymmetric monohydrosilanes, which are subsequently trapped with alkenes in a stereospecific fashion to build functionally diverse asymmetrically tetrasubstituted silanes. This general strategy combines readily available dihydrosilanes and alkenes to construct various enantioenriched silicon-stereogenic silanes, including 9-silafluorenes, Si-bridged ladder compounds, and benzosilolometallocenes, in a single step with good to excellent yields and enantioselectivities.
- Mu, Delong,Yuan, Wei,Chen, Shuyou,Wang, Na,Yang, Bo,You, Lijun,Zu, Bing,Yu, Peiyuan,He, Chuan
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supporting information
p. 13459 - 13468
(2020/09/09)
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- Enantioselective Silylation of Aliphatic C?H Bonds for the Synthesis of Silicon-Stereogenic Dihydrobenzosiloles
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A rhodium(I)-catalyzed enantioselective silylation of aliphatic C?H bonds for the synthesis of silicon-stereogenic dihydrobenzosiloles is demonstrated. This reaction involves a highly enantioselective intramolecular C(sp3)?H silylation of dihydrosilanes, followed by a stereospecific intermolecular alkene hydrosilylation leading to the asymmetrically tetrasubstituted silanes. A wide range of dihydrosilanes and alkenes displaying various functional groups are compatible with this process, giving access to a variety of highly functionalized silicon-stereogenic dihydrobenzosiloles in good to excellent yields and enantioselectivities.
- Guo, Yonghong,He, Chuan,Yang, Bo,Yang, Wu,You, Lijun
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supporting information
p. 22217 - 22222
(2020/10/02)
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- Visible-Light-Driven Nitrogen Radical-Catalyzed [3 + 2] Cyclization of Vinylcyclopropanes and N-Tosyl Vinylaziridines with Alkenes
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A visible light photoredox-promoted and nitrogen radical catalyzed [3 + 2] cyclization of vinylcyclopropanes and N-tosyl vinylaziridines with alkenes is developed. Key to the success of this process is the use of the readily tunable hydrazone as a nitrogen radical catalyst. Preliminary mechanism studies suggest that the photogenerated nitrogen radical undergoes reversible radical addition to the vinylcyclopropanes and N-tosyl vinylaziridines to enable their ring-opening C-C and C-N bond cleavage and ensuing cyclization with alkenes.
- Chen, Jia-Rong,Wu, Ya-Li,Xiao, Wen-Jing,Xu, Shuang-Hua,Zhao, Quan-Qing,Zhou, Xue-Song
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supporting information
(2020/03/13)
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- Vinyl polymerization versus [1,3] O to C rearrangement in the ruthenium-catalyzed reactions of vinyl ethers with hydrosilanes
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Two reactions, vinyl polymerization and [1,3] O to C rearrangement of vinyl ethers, are investigated in the ruthenium-catalyzed reaction with hydrosilanes. The reaction pathways are dependent on the substituents of the vinyl ether, in particular, those of the alkoxy group. Primary-, secondary-, and tertiary-alkyl vinyl ethers, ROCHCH2, are polymerized with ease to give the corresponding polymer in good yields. When R is electron-donating benzyl groups, the reaction does not give the polyvinyl ether but results in [1,3] O to C rearrangement to give the corresponding aldehyde, RCH2CHO in moderate to good yields. The rearrangement selectively proceeds when vinyl ethers having α-substituents are used as the starting materials to give the corresponding ketones in high yields. With catalytic amounts of hydrosilanes, the rearrangement gives ketones or aldehydes selectively. In sharp contrast, use of excess amounts of hydrosilanes leads to the rearrangement followed by reduction of the formed carbonyl group to give the corresponding silyl ethers in good yields. Nature of catalytically active species is discussed. Crown Copyright
- Harada, Nari-Aki,Nishikata, Takashi,Nagashima, Hideo
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supporting information; experimental part
p. 3243 - 3252
(2012/06/01)
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- Au(I) complexes-catalyzed transfer vinylation of alcohols and carboxylic acids
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Au(I) complexes-catalyzed transfer vinylation of alcohols and carboxylic acids has been achieved. The catalyst system consists of 2 mol % AuClPPh3 and 2 mol % AgOAc. Primary alcohols and secondary alcohols were converted into corresponding vinyl ethers in good yield (64-93%); however, tertiary alcohols showed poor reactivities. Carboxylic acids were also transformed into corresponding vinyl esters in good yield (78-96%).
- Nakamura, Aki,Tokunaga, Makoto
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p. 3729 - 3732
(2008/09/20)
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- Process for producing optically active compound
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A process for producing an optically active compound based on the hydrolysis of an alkenyl ester compound or the cleavage of an alkenyl ether compound. The process uses neither an acidic compound nor a basic compound, and rectants can be reacted in a high concentration. It does not necessitate a buffer, nutrient, etc. unlike enzymatic reactions or reactions using a microorganism. It is a simple process which attains a satisfactory production efficiency. The process, which is for producing an optically active carboxylic acid or optically active alcohol represented by the general formula (VI): (wherein R1, R2, and R3 are different groups; and A represents methylene, carbonyl, or a single bound), is characterized by causing water to act on an alkenyl ester or alkenyl ether represented by the general formula (I): (wherein R4, R5, and R6 each represents hydrogen, alkyl, etc.) in the presence of a specific transition metal complex having an optically active ligand.
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Page/Page column 7-8
(2008/06/13)
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- Hydrolysis of Alkenyl Esters and Ethers Catalyzed by Metal Complexes
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(Equation presented) Various kinds of transition metals catalyzed the hydrolysis of alkenyl esters and ethers under buffer-free, high concentration conditions compared to usual biocatalysts. Hydrolytic kinetic resolution of cis-2-tert-butylcyclohexyl vinyl ether was achieved by chiral (salen)Co complexes with good selectivity (krel = 10.0).
- Aoyama, Hiroshi,Tokunaga, Makoto,Hiraiwa, Shin-Ichiro,Shirogane, Yuki,Obora, Yasushi,Tsuji, Yasushi
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p. 509 - 512
(2007/10/03)
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- Efficient mercury-free preparation of vinyl and isopropenyl ethers of chiral secondary alcohols and α-hydroxyesters
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Mixed acetals 2a-h and 5a-d, readily deriving from the α-chiral alcohols 1a-h and ethyl vinyl ether or isopropenyl methyl ether, underwent selective elimination of primary alcohol upon treatment with triethylamine and trimethylsilyl trifluoromethanesulfon
- Dujardin, Gilles,Rossignol, Sandrine,Brown, Eric
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p. 1653 - 1656
(2007/10/02)
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- Cycloaddition of Nitrile Oxides to Homochiral Vinyl Ethers
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In the cycloaddition of a range of nitrile oxides with homochiral vinyl ethers the diastereoselectivity observed is dependent on the chiral auxiliary used.A brief comparison is made with the diastereoselectivity of the corresponding nitrosoalkene cycloaddition, and also to the nitrile oxide cycloaddition to chiral acrylic acid esters bearing the most successful auxiliaries from the vinyl ether study.
- Boa, Andrew N.,Dawkins, David A.,Hergueta, Antonio R.,Jenkins, Paul R.
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p. 953 - 960
(2007/10/02)
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The alkyl vinyl ethers 2b-8b (deriving from the alcohols 2a-8a) smoothly reacted with methyl E-benzylidenepyruvate 10 in the presence of catalytic amounts of Eu(fod)3 or Yb(fod)3 in refluxing hexane, thus leading to the dihydropyran
- Dujardin, Gilles,Rossignol, Sandrine,Molato, Samira,Brown, Eric
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p. 9037 - 9050
(2007/10/02)
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- Asymmetric syntheses of substituted dihydropyrans by Diels-Alder heterocycloadditions involving chiral vinyl ethers as dienophiles
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The alkyl vinyl ethers 2b-8b (deriving from the alcohols 2a-8a) smoothly reacted with methyl E-benzylidenepyruvate 1 in the presence of catalytic amounts of Eu(fod)3, thus leading to the endo cycloadducts 9-15 in high yields. The cycloadducts 1
- Dujardin,Molato,Brown
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p. 193 - 196
(2007/10/02)
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- SYNTHESIS OF CHIRAL SULFONYLMETHYL ISOCYANIDES, AND COMPARISON OF THEIR PROPENSITIES IN ASYMMETRIC INDUCTION REACTIONS WITH ACETOPHENONES
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Seven chiral analogues of tosylmethyl isocyanide (TosMIC) were synthesized in order to investigate and compare their ability to achieve asymmetric induction in base mediated reactions with acetophenone and trifluoracetophenone.Acid hydrolysis of the intermediate 2-oxazolines (10 and 11) gave optically active α-hydroxy aldehydes (12 and 13).
- Hundscheid, Frans J. A.,Tandon, Vishnu K.,Rouwette, Pieter H. F. M.,Leusen, Albert M. van
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p. 5073 - 5088
(2007/10/02)
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