- Asymmetric Photocatalytic C(sp3)-H Bond Addition to α-Substituted Acrylates
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Asymmetric functionalization of inert C(sp3)-H bonds is a straightforward approach to realize versatile bond-forming events, allowing the precise assembly of molecular complexity with minimal functional manipulations. Here, we describe an asymmetric photocatalytic C(sp3)-H bond addition to α-substituted acrylates by using tetrabutylammonium decatungstate (TBADT) as a hydrogen atom transfer (HAT) photocatalyst and chiral phosphoric acid as a chiral proton-transfer shuttle. This protocol is supposed to occur via a radical/ionic relay process, including a TBADT-mediated HAT to cleave the inert C(sp3)-H bond, a 1,4-radical addition, a back hydrogen abstraction, and an enantioselective protonation. A variety of inert C-H bond patterns and α-substituted acrylates are well tolerated to enable the rapid synthesis of enantioenriched α-stereogenic esters from simple raw materials.
- Dai, Zhen-Yao,Nong, Zhong-Sheng,Song, Shun,Wang, Pu-Sheng
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supporting information
p. 3157 - 3161
(2021/05/05)
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- Dehydrogenative Silylation of Alkenes for the Synthesis of Substituted Allylsilanes by Photoredox, Hydrogen-Atom Transfer, and Cobalt Catalysis
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A synergistic catalytic method combining photoredox catalysis, hydrogen-atom transfer, and proton-reduction catalysis for the dehydrogenative silylation of alkenes was developed. With this approach, a highly concise route to substituted allylsilanes has been achieved under very mild reaction conditions without using oxidants. This transformation features good to excellent yields, operational simplicity, and high atom economy. Based on control experiments, a possible reaction mechanism is proposed.
- Yu, Wan-Lei,Luo, Yong-Chun,Yan, Lei,Liu, Dan,Wang, Zhu-Yin,Xu, Peng-Fei
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supporting information
p. 10941 - 10945
(2019/07/17)
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- Polymeric depots for localization of agent to biological sites
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Provided herein are polymeric particles and compounds and processes that can be used to prepare polymer-based particles and methods of using those particles to localize or concentrate a subsequently delivered agent to an in vivo site.
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Page/Page column 64
(2019/04/26)
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- Synthesis method of terminal olefin type compound
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The invention discloses a synthesis method of a terminal olefin type compound. The synthesis method comprises the following steps: taking a phosphorus ylide compound as a raw material and carbon dioxide as a C1 synthon in an organic solvent; reacting in the presence of a reducing agent to prepare the terminal olefin type compound, wherein the mole ratio of the phosphorus ylide compound to the reducing agent is 1 to (1 to 6) and the pressure of carbon dioxide is 1 to 3atm. The synthesis method disclosed by the invention has the advantages of convenience for operation, moderate conditions, widesubstrate applicable range and high efficiency; the defects in the prior art are filled; the synthesis method takes the carbon dioxide as synthon and carbon dioxide can be effectively absorbed so thata greenhouse effect is effectively prevented.
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Paragraph 0050; 0052; 0053
(2018/09/21)
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- Transition-Metal-Free Reductive Deoxygenative Olefination with CO2
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A new transition-metal-free reductive deoxygenative olefination of phosphorus ylides with CO2, an abundant and sustainable C1 chemical feedstock, is described. This catalytic CO2 fixation afforded β-unsubstituted acrylates and vinyl ketones in good yields with broad scope and good functional group tolerance under mild reaction conditions. Cost-effective and easily handled polymethylhydrosiloxane was used as a reductant. Bis(silyl)acetal was proved to be the key intermediate in this reductive functionalization of CO2.
- Zhu, Dao-Yong,Li, Wen-Duo,Yang, Ce,Chen, Jie,Xia, Ji-Bao
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supporting information
p. 3282 - 3285
(2018/06/11)
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- SYSTEM AND METHOD FOR PREPARING AROMATIC DERIVATIVE
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A system for preparing an aromatic derivative is provided, including: a photo-bromination reaction section for performing a photocatalytic reaction of an aromatic hydrocarbon and a brominating agent to form an aromatic hydrocarbon bromide; a substitution reaction section for performing a substitution reaction of the an aromatic hydrocarbon bromide from the photo-bromination reaction section with an alkali base compound or an alkali carboxylate compound to form an aromatic derivative; and a regeneration unit for reacting an alkali metal bromide formed by the substitution reaction section with an acid to form a hydrobromic acid. The regeneration unit is in fluid communication with the photo-bromination reaction section, such that the hydrobromic acid is recycled to the photo-bromination reaction section. A method for preparing the aromatic derivative is also provided.
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Page/Page column 0087-0088
(2018/03/25)
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- Reductive Coupling of Acrylates with Ketones and Ketimines by a Nickel-Catalyzed Transfer-Hydrogenative Strategy
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Nickel-catalyzed coupling of benzyl acrylates with activated ketones and imines provides γ-butyrolactones and lactams, respectively. The benzyl alcohol byproduct released during the lactonization/lactamization event is relayed to the next cycle where it serves as the reductant for C?C bond formation. This strategy represents a conceptually unique approach to transfer-hydrogenative C?C bond formation, thus providing examples of reductive heterocyclizations where hydrogen embedded within an alcohol leaving group facilitates turnover.
- Buxton, Craig S.,Blakemore, David C.,Bower, John F.
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supporting information
p. 13824 - 13828
(2017/10/24)
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- ZINC COMPLEX
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A zinc complex characterized in exhibiting an octahedral structure and being configured from repeating units represented by general formula (I): wherein L represents a linker region, and R1 represents a C1-4 alkyl group, which can have a halogen atom.
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Paragraph 0200
(2016/05/19)
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- Chemoselective Transesterification of Acrylate Derivatives for Functionalized Monomer Synthesis Using a Hard Zinc Alkoxide Generation Strategy
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A new practical method for the synthesis of functionalized acrylate derivatives with the view to prepare functional polymers was explored. Hard zinc alkoxide generation enabled the highly chemoselective transesterification of acrylate derivatives over the undesired conjugate addition, which caused polymerization. The combined use of the catalytic zinc cluster Zn4(OCOCF3)6O and 4-(dimethylamino)pyridine delivered various functionalized acrylate derivatives through the transesterification of commercially available methyl acrylate derivatives with functionalized alcohols under mild conditions.
- Nakatake, Daiki,Yazaki, Ryo,Ohshima, Takashi
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supporting information
p. 3696 - 3699
(2016/08/20)
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- An Effective Method for the Construction of Esters Using Cs2CO3 as Oxygen Source
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An effective method for the construction of esters from acyl chloride and halohydrocarbon using Cs2CO3 as an oxygen source was achieved for the first time. The methodology has a wide scope of substrates and can be scaled up. The study of a preliminary reaction mechanism demonstrated that the O in the products comes from Cs2CO3 and this esterification proceeds through a free radical reaction. It was also found that CO2 can also be used in this esterification reaction as an oxygen source.
- Ren, Lanhui,Wang, Lianyue,Lv, Ying,Li, Guosong,Gao, Shuang
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supporting information
p. 5172 - 5175
(2015/11/24)
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- Ester manufacturing method (by machine translation)
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PROBLEM TO BE SOLVED: To produce an ester compound by transesterification using an inexpensive and low toxic inorganic compound. SOLUTION: Transesterification of an ester compound and an alcohol compound is carried out under the presence of lanthanum nitrate (for example, lanthanum nitrate hexahydrate) and a phosphine compound (for example, tri-n-octylphosphine), thereby obtaining the ester product. For example, transesterification of dimethyl carbonate and benzyl alcohol is carried out under the presence of 1 mol% of lanthanum nitrate hexahydrate, and 2 mol% of tri-n-octylphosphine, thereby obtaining benzyl methylcarbonate at a yield of >99%. COPYRIGHT: (C)2012,JPO&INPIT
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Paragraph 0087; 0088
(2017/02/17)
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- A basic germanodecatungstate with a - 7 charge: Efficient chemoselective acylation of primary alcohols
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The synthesis of highly negatively charged polyoxometalates with electrically and structurally controlled uniform basic sites can lead to the unique base catalysis. In this work, a γ-Keggin germanodecatungstate, [γ-HGeW10O36]7- (A), having a -7 charge was, for the first time, successfully synthesized by the reaction of [γ-H2GeW10O36]6- with one equivalent of [(n-C4H9)4N]OH under non-aqueous conditions. The activities of germanodecatungstates for base-catalyzed reactions dramatically increased with increase in the number negative charges from -6 to -7. In the presence of A, various combinations of acylating agents and primary alcohols including those with acid-sensitive functional groups chemoselectively gave the desired acylated products in high yields even under the stoichiometric conditions.
- Sugahara, Kosei,Satake, Naoto,Kamata, Keigo,Nakajima, Takahito,Mizuno, Noritaka
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supporting information
p. 13248 - 13252
(2015/01/09)
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- A new method using 2-chloro-4,6-dimethoxy-1,3,5-triazine for facile elimination of dimethylamino group in Eschenmoser's methylenation for synthesis of α,β-unsaturated esters
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A facile one-step method for the elimination of the dimethylamino group in Eschenmoser's methylenation has been developed using a combination of 2-chloro-4,6-dimethoxy-1,3,5-triazine and triethylamine. The chemoselective elimination of the dimethylamino group occurred in compounds possessing either a diethylamino group or an alkylsulfanyl group.
- Yamada, Kohei,Masaki, Kazumasa,Hagimoto, Yuri,Kamiya, Seina,Kunishima, Munetaka
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supporting information
p. 1758 - 1760
(2013/03/29)
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- In situ generated "lanthanum(iii) nitrate alkoxide" as a highly active and nearly neutral transesterification catalyst
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In situ generated lanthanum(iii) nitrate alkoxide is a highly active and nearly neutral transesterification catalyst, which can promote non-epimerized transesterification of α-substituted chiral carboxylic esters under reflux conditions.
- Hatano, Manabu,Kamiya, Sho,Ishihara, Kazuaki
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supporting information
p. 9465 - 9467
(2012/10/29)
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- Fast synthesis employing a microwave assisted neat protocol of new monomers potentially useful for the preparation of PDLC films
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It has been repor ted that the length of the molecular chain and the rigidity of molecules influence the structure of the polymer network in PDLC films and hence the electro-optical proper ties of the composites. Herein, a series of new aromatic monomeric monomethacrylates, bismethacrylates and monovinylbenzene derivatives with a mesogenic core were successfully synthesized under microwave irradiation. The microwave assisted synthesis resulted in decreased reaction times, reduced solvent requirement, increased operational simplicity, and in most cases, improved yields and selectivity. Versita Sp. z o.o.
- Barros, M. Teresa,Mouquinho, Ana I.,Petrova, Krasimira T.,Saavedra, Mara D.,Sotomayor, Joao C.
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experimental part
p. 557 - 566
(2012/04/10)
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- Selective pyrolysis of bifunctional compounds: gas-phase elimination of carbonate-ester functionalities
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Compounds containing both carbonate and ester functionalities were synthesized and then subjected to online-GC gas-phase pyrolysis. The carbonate groups were cleaved selectively in all elimination reactions. The end products of the reaction were found to be affected by the nature of the substrate. The presence of hydrogen and carbonyl substituents on the carbon β to the carbonate group resulted in further product decomposition through a concerted six-membered transition state. Results from flash vacuum pyrolysis (FVP) and analysis of the GC data indicate that the cleavage of the carbonate group is fast, and that the slower secondary decomposition reactions are independent of the presence of the carbonate group. Spectroscopic analyses of the products are reported.
- Al-Azemi, Talal F.,Dib, Hicham H.,Al-Awadi, Nouria A.,El-Dusouqui, Osman M.E.
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p. 4126 - 4134
(2008/09/20)
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- A direct functionalization of tertiary alkyl bromides with O-, N-, and C-nucleophiles
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Silver oxide used in stoichiometric amounts promoted the direct functionalization of tert-alkyl bromides and provided the desired adducts in 39-96% isolated yield. Reaction of tert-bromides with carboxylic acids yielded esters, with alcohols and phenols yielded alkyl and aryl ethers, with amines and anilines yielded selectively mono-alkylated amines and anilines, and with a C-nucleophile yielded an all-carbon quaternary hydrocarbon. The method was applied to a sequential alkylation of a primary amine with two different alkyl bromides yielding selectively a tertiary amine with three different substituents in one-pot.
- Vachal, Petr,Fletcher, Joan M.,Hagmann, William K.
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p. 5761 - 5765
(2008/02/09)
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- Novel monovinyl methacrylic monomers containing secondary functionality for ultrarapid polymerization: Steady-state evaluation
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Experimental investigations were made into the effects of monomer structure and functionality on free-radical polymerization kinetics. A more comprehensive understanding of how structural characteristics, monomer traits, and polymerization conditions influence the polymerization mechanisms and network evolution was desired. Variations in the nature of the monomers' secondary functionality and the terminal substitution were the primary variables examined. The three factors hypothesized as important to the advantageous polymerization characteristics observed are hydrogen bonding, hydrogen abstraction, and the electronic characteristics of the monomer. The experimental evaluations presented clearly demonstrate that each of these mechanisms contributes to the reactivity of these monomers and the networks that they form. The combination of these factors leads to cross-linked network formation and enhanced polymerization kinetics, i.e., monovinyl monomers with reactivities that rival those of commonly used divinyl monomers.
- Berchtold, Kathryn A.,Nie, Jun,Stansbury, Jeffrey W.,Hacioglu, Bilge,Beckel, Eric R.,Bowman, Christopher N.
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p. 3165 - 3179
(2007/10/03)
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- Ruthenium-catalyzed carbonylation of allene: Direct synthesis of methacrylates and methacrylamides
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Carbonylation reactions of allene in alcohols and amines in the presence of a ruthenium carbonyl catalyst under mild conditions gave methacrylates and methacrylamides, respectively, in good yields with an atom economy of 100%.
- Zhou, Da-Yang,Yoneda, Eiji,Onitsuka, Kiyotaka,Takahashi, Shigetoshi
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p. 2868 - 2869
(2007/10/03)
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- Direct ester condensation from a 1:1 mixture of carboxylic acids and alcohols catalyzed by hafnium(IV) or zirconium(IV) salts
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To promote atom efficiency in synthesis and to avoid the generation of environmental waste, the use of stoichiometric amounts of condensing reagents or excess substrates should be avoided. In esterification, excess amounts of either carboxylic acids or alcohols are normally needed. We found that the direct condensation of equimolar amounts of carboxylic acids and alcohols could be achieved using hafnium(IV) or zirconium(IV) salts. These metal salts are highly effective as catalysts for the selective esterification of primary alcohols with carboxylic acids in the presence of secondary alcohols or aromatic alcohols. The present methods can be applied to direct polyesterification and may be suitable for large-scale operations.
- Ishihara, Kazuaki,Nakayama, Masaya,Ohara, Suguru,Yamamoto, Hisashi
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p. 8179 - 8188
(2007/10/03)
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- A novel reaction medium: Perfluorocarbon fluids
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The use of perfluorocarbon (PFC) fluids such as perfluorinated alkanes and alkylamines as inert medium for organic reactions is demonstrated with advantages summarized. PFC fluids have been found to be very useful in organic reactions where a medium is needed for refluxing and for separating a low boiling component, or where an extremely nonpolar/inert medium is required for reactions carried out under vigorous conditions. The PFC fluids are not miscible with most organic compounds and therefore offer good separatory properties that common organic solvents do not have.
- Zhu
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p. 953 - 954
(2007/10/02)
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- Disinfectant polymeric coatings for hard surfaces
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Liquid disinfectant compositions are disclosed which can be used to surface-coat substrates with polymeric films which are adherent, water-resistant and which can impart prolonged germicidal properties to the treated surfaces.
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- Biosynthesis of Sulfur Compounds. Investigations of the Biosinthesis of Asparagusic Acid.
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Investigations of the biosynthesis of the naturally occuring 1,2-dithiolane asparagusic acid (1) in Asparagus officinalis have shovn that the substance is derived from inobutyric acid via the intermediacy of methacrylic acid, 2-methyl-3-mercaptopropionic acid, and S-(2-carboxy-n-propyl) cysteine.The conversion of isobutyric acid to methacrylic acid in Asparagus has also been shown to proceed by oxidation of the 2-pro-S methyl group of isobutyrate.Finally, the absolute configuration of naturally occuring S-(2-carboxy-n-propyl)cysteine has been determined.
- Parry, Ronald J.,Mizusawa, A.E.,Chiu, I.C.,Naidu, M.V.,Ricciardone, M.
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p. 2512 - 2521
(2007/10/02)
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- ETUDE DE LA REACTION CHLOROCARBENE-ACETALS DE CETENES. I. SYNTHESE D'ESTERS α,β-ETHYLENIQUES.
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The reaction of chloro, chloromethyl and chlorophenyl carbenoids with ketene alkylsilylacetals has been studied.Excellent yields of cyclopropanation were observed and the unstable chlorocyclopropanone acetals formed were thermally rearranged in high yield into α-substituted α,β-ethylenic esters.This new method for the synthesis of unsaturated esters appeared complementary of the known-ones.
- Slougui, N.,Rousseau, G.
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p. 2643 - 2652
(2007/10/02)
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- Acyclic Stereoselection. 22. Diastereofacial Selectivity in the Lewis Acid Mediated Reactions of Allylsilanes with Chiral Aldehydes and Enones
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The Lewis acid mediated reactions of chiral aldehydes 1-4 and enones 5-8 with allylsilanes 9 and 10 have been investigated.With aldehyde 1 and enones 5-7, modest diastereofacial preferences are seen, in the sense predicted by application of Felkin's model for asymmetric induction.Aldehydes 2-4 and enone 8 appear to react by way of chelated intermediates.With these four compounds, the diastereofacial preferences are rather large and are in the sense that is consistend with attack of the allylsilane on the least hindered face of the chelated intermediate.In the reaction of the trans and cis enones 6 and 8 with allyltrimethylsilane, a dramatic reversal of diastereofacial preference is observed; enone 6 gives a 84:14 ratio of products, while enone 8 provides a 10:90 mixture of the same products.
- Heathcock, Clayton H.,Kiyooka, Syun-ichi,Blumenkopf, Todd A.
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p. 4214 - 4223
(2007/10/02)
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