- Neutral-eosin Y-catalyzed regioselective hydroacylation of aryl alkenes under visible-light irradiation
-
Styrene derivatives were hydroacylated with exclusive anti-Markovnikov selectivity by using neutral eosin Y as a direct hydrogen-atom-transfer (HAT) catalyst under visible-light irradiation. Aldehydes and styrenes with various substituents were tolerated (>20 examples), giving the corresponding products in moderate to high yields. The key acyl radical intermediate was generated from a direct HAT process induced by photoexcited eosin Y. Subsequent addition to styrenes and a reverse HAT process generated the ketone products.
- Liu, Haiwang,Xue, Fei,Wang, Mu,Tang, Xinxin,Wu, Jie
-
supporting information
p. 406 - 410
(2020/12/30)
-
- Catalyst-controlled regiodivergent 1,2-difunctionalization of alkenes with two carbon-based electrophiles
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Regiodivergent catalysis provides an efficient strategic approach for the construction of architecturally different molecules from the same starting materials. In this field, the intermolecular regiodivergent 1,2-difunctionalization of alkenes with two electrophiles is still a challenging task. A ligand-controlled, nickel-catalyzed regiodivergent dicarbofunctionalization of alkenes using both aryl/vinyl halides and acetals as electrophiles under mild reductive reaction conditions has been accomplished. This study provides a general approach to accessing both β-methoxyl esters and γ-methoxyl esters from readily available acrylates, aryl halides and acetals. Experimental mechanistic evidence supports that the difference in regioselective outcomes is attributed to the ligand tuning the reactivity of the nickel catalyst, which results in different catalytic cycles operating for these two reaction conditions.
- Belal, Md.,Li, Zheqi,Yin, Guoyin,Zhu, Lei
-
-
- REDUCTION METHOD AND REDUCTION PRODUCT OF ALKENYL ACTIVE METHYLENE COMPOUND
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Disclosed are a reduction method and reduction product of an alkenyl active methylene compound. The reduction reaction comprises the following steps: taking an alkenyl active methylene compound as a substrate, a metal hydride as a reducing agent, and a palladium compound as a catalyst, performing a reduction reaction to obtain a reduction product, and then reducing the alkenyl active methylene compound. The reduction system is a simple method for reducing the alkenyl active methylene compound, and the used hydride and palladium compound catalyst are both reagents that could easily be obtained in a laboratory. Compared with conventional hydrogen hydrogenation methods and reduction methods of reducing agents, the method is easier to operate, higher in safety, mild in conditions, and high in reaction yield, a reaction in a one-pot two-step manner can be achieved, and high atom economy and step economy can be obtained.
- -
-
Paragraph 0019-0020
(2021/07/02)
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- Catalytic asymmetric construction of C-4 alkenyl substituted pyrazolone derivatives bearing multiple stereoelements
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An organocatalytic asymmetric process was reported for the sterically precise construction of C-4 alkenyl substituted pyrazolone derivatives bearing multiple stereoelements. A series of interesting products featuring the union of a centrally chiral pyrazolone moiety and an axially chiral styrene unit were obtained in high yield with excellent diastereoselectivity and enantioselectivity (up to 99% ee, >20?:?1 dr). The process has the characteristics of mild reaction conditions, simple operation and broad substrate scope. The result of gram-scale reaction indicates that the reaction has good practicability.
- Qu, Jingping,Wang, Baomin,Wang, Wenyao,Wei, Shiqiang,Zhang, Wande
-
supporting information
p. 6550 - 6553
(2021/07/07)
-
- Complementing Pyridine-2,6-bis(oxazoline) with Cyclometalated N-Heterocyclic Carbene for Asymmetric Ruthenium Catalysis
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A strategy for expanding the utility of chiral pyridine-2,6-bis(oxazoline) (pybox) ligands for asymmetric transition metal catalysis is introduced by adding a bidentate ligand to modulate the electronic properties and asymmetric induction. Specifically, a ruthenium(II) pybox fragment is combined with a cyclometalated N-heterocyclic carbene (NHC) ligand to generate catalysts for enantioselective transition metal nitrenoid chemistry, including ring contraction to chiral 2H-azirines (up to 97 % ee with 2000 TON) and enantioselective C(sp3)?H aminations (up to 97 % ee with 50 TON).
- Li, Long,Han, Feng,Nie, Xin,Hong, Yubiao,Ivlev, Sergei,Meggers, Eric
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supporting information
p. 12392 - 12395
(2020/06/10)
-
- Development of coumarine derivatives as potent anti-filovirus entry inhibitors targeting viral glycoprotein
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Filoviruses, including Ebolavirus (EBOV), Marburgvirus (MARV) and Cuevavirus, cause hemorrhagic fevers in humans with up to 90% mortality rates. In the 2014–2016 West Africa Ebola epidemic, there are 15,261 laboratory confirmed cases and 11,325 total deaths. The lack of effective vaccines and medicines for the prevention and treatment of filovirus infection in humans stresses the urgency to develop antiviral therapeutics against filovirus-associated diseases. Our previous study identified a histamine receptor antagonist compound CP19 as an entry inhibitor against both EBOV and MARV. The preliminary structure-activity relationship (SAR) studies of CP19 showed that its piperidine, coumarin and linker were related with its antiviral activities. In this study, we performed detailed SAR studies on these groups with synthesized CP19 derivatives. We discovered that 1) the piperidine group could be optimized with heterocycles, 2) the substitution groups of C3 and C4 of coumarin should be relatively large hydrophobic groups and 3) the linker part should be least substituted. Based on the SAR analysis, we synthesized compound 32 as a potent entry inhibitor of EBOV and MARV (IC50 = 0.5 μM for EBOV and 1.5 μM for MARV). The mutation studies of Ebola glycoprotein and molecular docking studies showed that the coumarin and its substituted groups of compound 32 bind to the pocket of Ebola glycoprotein in a similar way to the published entry inhibitor compound 118a. However, the carboxamide group of compound 32 does not have strong interaction with N61 as compound 118a does. The coumarin skeleton structure and the binding model of compound 32 elucidated by this study could be utilized to guide further design and optimization of entry inhibitors targeting the filovirus glycoproteins.
- Gao, Yinyi,Cheng, Han,Khan, Sameer,Xiao, Gaokeng,Rong, Lijun,Bai, Chuan
-
-
- Carbocation Lewis Acid TrBF4-Catalyzed 1,2-Hydride Migration: Approaches to (Z)-α,β-Unsaturated Esters and α-Branched β-Ketocarbonyls
-
Carbocation Lewis acid TrBF4-catalyzed 1,2-hydride migration of α-alkyldiazoacetates themselves or in situ-generated cross-coupling adducts of aldehydes and α-alkyldiazoacetates has been developed, affording (Z)-α,β-unsaturated esters and α-branched β-ketocarbonyls, respectively, in good yields and with high regioselectivities.
- Duan, Depeng,Liu, Yongjun,Lv, Jian,Shang, Wansong
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supporting information
(2019/10/08)
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- Environmentally benign nucleophilic substitution reaction of arylalkyl halides in water using CTAB as the inverse phase transfer catalyst
-
An environmentally benign, practically scalable and highly selective C-arylalkylation of active methylene compounds is developed using CTAB as the inverse phase transfer catalyst in water. The methodology developed is elaborated into the one-pot synthesis of quinoline derivatives and also applicable to the regioselective N-aralkyl of 2-pyridones.
- Godha, Atul K.,Thiruvengadam, Jayaraman,Abhilash, Viswanadhan,Balgi, Prajwal,Narayanareddy,Vignesh, Kumaresan,Gadakh, Amol V.,Sathiyanarayanan,Ganesh, Sambasivam
-
supporting information
p. 16041 - 16045
(2019/10/28)
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- The Employment of Sodium Hydride as a Michael Donor in Palladium-catalyzed Reductions of α, β-Unsaturated Carbonyl Compounds
-
Sodium hydride was employed as a Michael donor under the catalysis of PdCl2 for 1,4-conjugate reductions of α, β-unsaturated carbonyl compounds, which features operational simplicity, mild conditions and high atom-economy. The merits of NaH as a reductant were demonstrated by the one-pot or cascade reactions for the syntheses of complex molecules. (Figure presented.).
- Liu, Ye,Mao, Yujian,Hu, Yanwei,Gui, Jingjing,Wang, Liang,Wang, Wei,Zhang, Shilei
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p. 1554 - 1558
(2019/02/16)
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- Highly Carbon-Selective Monofluoromethylation of β-Ketoesters with Fluoromethyl Iodide
-
A highly carbon-selective monofluoromethylation of a broad range of β-ketoesters with fluoromethyl iodide under mild conditions is described. The uses of lithium tert-butoxide as the base and diglyme as the solvent made great contributions to the high C/O regioselectivity.
- Ding, Tianqi,Jiang, Lvqi,Yang, Jie,Xu, Yimin,Wang, Guixiang,Yi, Wenbin
-
supporting information
p. 6025 - 6028
(2019/08/20)
-
- Method for synthesizing beta-keto ester through copper catalysis
-
The invention relates to a method for synthesizing beta-keto ester by copper catalysis, which comprises the following steps of dissolving ethyl acylacetate and halogenated hydrocarbon in an organic solvent, adding a copper catalyst and alkali, reacting at 60-90 DEG C for 12-18 hours, and separating and purifying to obtain the beta-keto ester. Compared with the prior art, the method has the advantages of simple and green synthesis process, excellent selectivity, higher yield and wide substrate range, and has the wide application value in the fields of biology, pharmaceutical chemistry industryand the like.
- -
-
Paragraph 0022-0024
(2019/12/02)
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- Reduction method and reduction product of alkenyl active methylene compound
-
The invention discloses a reduction method and reduction product of an alkenyl active methylene compound. The reduction reaction comprises the following steps: taking the alkenyl active methylene compound as a substrate, a metal hydride as a reducing agent, a palladium compound as a catalyst, performing a reduction reaction to obtain the reduction product, and then reducing the alkenyl active methylene compound. The reduction system of the invention is a simple method for reducing the alkenyl active methylene compound, used hydride and a palladium compound catalyst are all easily obtained reagents in the laboratory, compared with the conventional hydrogen hydrogenation method and the reduction method of the reducing agent, the method is easier to operate, higher in safety, mild in conditions and high in reaction yield, and can be reacted in a one-pot two-step manner, thereby having very high atom economy and step economy.
- -
-
Paragraph 0017
(2019/01/16)
-
- Method for preparing alpha-alkyl-beta-ketone ester compound
-
The invention discloses a method for preparing an alpha-alkyl-beta-ketone ester compound shown as a formula (I). The method comprises the following steps: a 1,4-dihydropyridine ester compound shown asa formua (III) is taken as a reducing agent, and under existence of a Lewis acid catalyst, a compound in a formula (II) is subjected to a reduction reaction to obtain the alpha-alkyl-beta-ketone ester compound shown as the formula (I). The method has the advantages of simple operation, mild condition and environmental protection, and is suitable for a plurality of substrates, and the yield can reach as highest as 95%. By using the method of the invention, a plurality of alpha-alkyl-beta-ketone ester compounds can be efficiently prepared, types of medical intermediates are enriched, and the method has an excellent industrial application prospect.
- -
-
Paragraph 0035-0052
(2018/05/01)
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- Enantioselective and Diastereoselective Ir-Catalyzed Hydrogenation of α-Substituted β-Ketoesters via Dynamic Kinetic Resolution
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An iridium/f-amphol catalytic system for the enantioselective hydrogenation of α-substituted β-ketoesters via dynamic kinetic resolution is reported. The desired anti products were obtained in high yields (up to 98%) with good diastereoselectivity (up to 96:4 diastereometic ratio (dr)) and excellent enantioselectivity (up to >99% enantiomeric excess (ee)). A catalytic model is proposed to explain the stereoselectivity.
- Gu, Guoxian,Lu, Jiaxiang,Yu, Ouran,Wen, Jialin,Yin, Qin,Zhang, Xumu
-
supporting information
p. 1888 - 1892
(2018/04/16)
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- Thiourea catalysed reduction of α-keto substituted acrylate compounds using Hantzsch ester as a reducing agent in water
-
The first method for the reduction of α-keto substituted acrylate compounds by Hantzsch ester in water under the catalysis of thiourea has been developed. The products were isolated in moderate to high yields (38-95%). These products are important intermediates in the synthesis of a series of natural products and other biologically active molecules.
- Weng, Guanglin,Ma, Xiaobo,Fang, Dongmei,Tan, Ping,Wang, Lijiao,Yang, Linlin,Zhang, Yuanyuan,Qian, Shan,Wang, Zhouyu
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p. 22909 - 22912
(2017/07/10)
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- Room Temperature, Reductive Alkylation of Activated Methylene Compounds: Carbon-Carbon Bond Formation Driven by the Rhodium-Catalyzed Water-Gas Shift Reaction
-
The rhodium-catalyzed water-gas shift reaction has been demonstrated to drive the reductive alkylation of several classes of activated methylene compounds at room temperature. Under catalysis by rhodium trichloride (2-3 mol %), carbon monoxide (10 bar), water (2-50 equiv), and triethylamine (2.5-7 equiv), the scope has been successfully expanded to cover a wide range of alkylating agents, including aliphatic and aromatic aldehydes, as well as cyclic ketones, in moderate to high yields. This method is comparable to, and for certain aspects, surpasses the established reductive alkylation protocols.
- Denmark, Scott E.,Ibrahim, Malek Y. S.,Ambrosi, Andrea
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p. 613 - 630
(2017/06/05)
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- Tunable Aerobic Oxidative Hydroxylation/Dehydrogenative Homocoupling of Pyrazol-5-ones under Transition-Metal-Free Conditions
-
A practical and tunable transition-metal-free aerobic oxidation of pyrazol-5-ones preparing either 4-hydroxypyrazoles (via C-H hydroxylation) or bispyrazoles (via dehydrogenative homocoupling) is described. The K2CO3/dioxane reagent system predominately promoted hydroxylation to deliver the α-hydroxylated pyrazoles. In contrast, the formation of bispyrazoles was overwhelmingly preferred with CH3CN as the reaction medium without any additives.
- Sheng, Xuguang,Zhang, Jinlong,Yang, Huameng,Jiang, Gaoxi
-
supporting information
p. 2618 - 2621
(2017/05/24)
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- Catalyst-free chemoselective reduction of the carbon-carbon double bond in conjugated alkenes with Hantzsch esters in water
-
A simple, efficient and green protocol for chemoselective reduction of carbon-carbon double bond in conjugated alkenes with Hantzsch esters is described. Without any additional catalysts, a series of conjugated alkenes with strong electron-withdrawing groups were reduced in water with excellent yield. Functional groups such as nitrile, ester, nitro, fluoro, chloro, bromo, furanyl and benzyl are all tolerated by the reaction conditions employed. The Royal Society of Chemistry.
- He, Qi,Xu, Zhihong,Jiang, Dehong,Ai, Wensi,Shi, Ronghua,Qian, Shan,Wang, Zhouyu
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p. 8671 - 8674
(2014/03/21)
-
- Heck reaction of Baylis-Hillman adducts with iodobenzenes using a catalytic amount of Pd/C under solvent-free conditions
-
The reaction of Baylis-Hillman adducts with iodobenzenes using commercially available palladium-on-carbon as a catalyst under solvent-free conditions afforded the corresponding coupling products, α-benzyl-β-keto esters, in high to excellent yields. The reactions are very efficient.
- Kim, Hyun-Soo,Lee, Sang-Jin,Choi, Boram,Yoon, Cheol Min
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p. 3161 - 3164
(2012/11/13)
-
- Expedient synthesis of highly substituted pyrroles via tandem rearrangement of α-diazo oxime ethers
-
An efficient rhodium-catalyzed synthesis of 2H-azirines and pyrroles has been developed. Novel rearrangement of α-oximino ketenes derived from α-diazo oxime ethers provides 2H-azirines bearing quaternary centers and allows for subsequent rearrangement to highly substituted pyrroles in excellent yields.
- Jiang, Yaojia,Chan, Wei Chuen,Park, Cheol-Min
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supporting information; scheme or table
p. 4104 - 4107
(2012/04/10)
-
- Iodine-mediated synthesis of 3 H -indoles via intramolecular cyclization of enamines
-
(Figure presented) The synthesis of 3H-indoles was achieved via the iodine-mediated intramolecular cyclization of enamines. A wide variety of 3H-indole derivatives bearing multifunctional groups were obtained in good to high yields under transition metal-free reaction conditions.
- He, Zhiheng,Li, Huanrong,Li, Zhiping
-
supporting information; experimental part
p. 4636 - 4639
(2010/09/15)
-
- Ethynyl-1,2-benziodoxol-3(1H)-one (EBX): An exceptional reagent for the ethynylation of keto, cyano, and nitro esters
-
Hot alkyne! The in situ generation of ethynyl-1,2-benziodoxol-3(1H)-one (EBX) from a silyl-protected reagent by using TBAF is reported. EBX displayed exceptional acetylene transfer ability onto stabilized enolates (see scheme), even at -78 □°C. The mild reaction conditions allowed the first ethynylation reactions of linear keto, cyano, and nitro esters in high yields to give all-carbon quaternary centers or non-natural amino acids after selective reduction of the nitro group.
- Gonzalez, Davinia Fernandez,Brand, Jonathan P.,Waser, Jerome
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supporting information; experimental part
p. 9457 - 9461
(2010/10/03)
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- Nájera oxime-derived palladacycles catalyze intermolecular Heck reaction with Morita-Baylis-Hillman adducts. An improved and highly efficient synthesis of α-benzyl-β-ketoesters
-
An improved and highly efficient synthesis of several α-benzyl-β-ketoesters from Morita-Baylis-Hillman adducts is described. These adducts were used as substrates for an intermolecular Heck reaction catalyzed by a Na?jera oxime-derived palladacycles. These efficient catalytic conditions probed to be very selective providing only the corresponding functionalized β-ketoesters in high yield with no decarboxylation product. It seems that the method herein described is one of the most efficient for the synthesis of α-benzyl-β-ketoesters.
- Ferreira, Bruno R.V.,Pirovani, Rodrigo V.,Souza-Filho, Luis G.,Coelho, Fernando
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experimental part
p. 7712 - 7717
(2009/12/03)
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- Dynamic kinetic resolution in the asymmetrie synthesis of β-amino acids by organocatalytic reduction of enamines with trichlorosilane
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A new methodology based on the organocatalytic asymmetric hydrosilylation of enamines that allows a direct access to a range of β3 and β2.3-amino acid derivatives was presented. The results show a successful reduction of aromatic substrates, a sterically more hindered ortho-substituted derivatives, and the thiophenyl analogue exhibiting lower reactivity. Fast enamine-imine equilibration is crucial as imines are chiral but racemic, while α-alkyl β-amino acids can be accessed by the symmetrical Mannich reaction. The α-alkyl derivatives have relative and absolute configuration due to their reduction with LiAlH4 into a known amino alcohols. Predominant formation of the anti isomer in 3o is consistent with conformation of the imine intermediate in the catalytic reduction.
- Malkov, Andrei V.,Stoncius, Sigitas,Vrankova, Kvetoslava,Arndt, Matthias,Kocovsky, Pavel
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supporting information; experimental part
p. 8082 - 8085
(2009/09/29)
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- An unusual dianion equivalent from acylsilanes for the synthesis of substituted β-keto esters
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The reaction of lithiated diazo esters with acylsilanes generates a remarkable intermediate en route to highly substituted β-keto esters. The Royal Society of Chemistry.
- Galliford, Chris V.,Scheidt, Karl A.
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p. 1926 - 1928
(2008/12/22)
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- The first successful intermolecular Heck reaction of Baylis-Hillman adducts: synthesis of β-aryl substituted Baylis-Hillman adducts
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The first successful intermolecular Heck reaction between Baylis-Hillman adducts and aryl iodides was achieved under the conditions comprising Pd(OAc)2/n-Bu4NBr/KOAc in CH3CN.
- Kim, Jeong Mi,Kim, Ko Hoon,Kim, Taek Hyeon,Kim, Jae Nyoung
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p. 3248 - 3251
(2008/09/21)
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- Transfer hydrogenation of activated C=C bonds catalyzed by ruthenium amido complexes: Reaction scope, limitation, and enantioselectivity
-
(Chemical Equation Presented) It was found that the chemoselectivity could be completely switched from C=O to C=C bonds in the transfer hydrogenation of activated α,β-unsaturated ketones catalyzed by diamine-ruthenium complex. Moreover, this addition via metal hydride had been applied to the reduction of various activated olefins. The electron-withdrawing ability of functional groups substituted on C=C bonds at the α- or β-position had strong influence on the reactivity. In addition, a wide variety of chiral diamine-Ru(II)-(arene) systems was investigated to explore the asymmetric transfer hydrogenation of prochiral α,α-dicyanoolefins. Two parameters had been systematically studied, (i) the structure of the N-sulfonylated chiral diamine ligands, in which several chiral diamines substituted on the benzene ring of DPEN were first reported, and (ii) the structure of the metal precursors, and high enantioselectivitiy (up to 89% ee) at the β-carbon was obtained.
- Xue, Dong,Chen, Ying-Chun,Cui, Xin,Wang, Qi-Wei,Zhu, Jin,Deng, Jin-Gen
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p. 3584 - 3591
(2007/10/03)
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- Simple preparation of α-diazo esters
-
(Chemical Equation Presented) The TiCl4-mediated reaction of an ester with benzoyl chloride results in high yields of the α-benzoylated ester. Diazo transfer of the benzoylated ester utilizing p- acetoamidobenzenesulfonyl azide affords the α-diazo ester in good yield. Using this simplified procedure, it is easy to prepare gram quantities of α-diazo esters.
- Taber, Douglass F.,Sheth, Ritesh B.,Joshi, Pramod V.
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p. 2851 - 2854
(2007/10/03)
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- Preparation of β-keto esters and β-diketones by C-acylation/deacetylation of acetoacetic esters and acetonyl ketones with 1-acylbenzotriazoles
-
Acyl-, aroyl-, and heteroaroyl-acetic esters 6a-f and 8a-1 are prepared by reactions of 1-acylbenzotriazoles 1a-k with acetoacetic esters 5 or 7a,b in the presence of sodium hydride followed by regioselective deacetylation. Similar C-acylation/deacetylati
- Katritzky, Alan R.,Wang, Zuoquan,Wang, Mingyi,Wilkerson, Chavon R.,Hall, C. Dennis,Akhmedov, Novruz G.
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p. 6617 - 6622
(2007/10/03)
-
- HIGH YIELD SYNTHESIS OF α PROPARGYLIC ACRYLIC ESTER : A GENERAL ACCESS TO α SUBSTITUTED ACRYLIC ESTERS
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A heterogeneous mediated, high yield, monopropargylation of ethyl benzoylacetate followed by a methylenation reaction using a formaldehyde addition-benzoyl elimination mechanism is described.This useful method is extended to the synthesis of α substituted acrylic esters.
- Queignec, Rene,Kirschleger, Bernard,Lambert, Francois,Aboutaj, Mohammed
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p. 1213 - 1224
(2007/10/02)
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- "Wolf and lamb" reactions: Equilibrium and kinetic effects in multipolymer systems
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Two reagents reacting avidly with each other in solution are rendered mutually inactive by attaching each to a separate batch of insoluble polymer. Two-stage reactions in which a soluble reagent reacts first with one polymeric reagent and the product with the second polymeric reagent afford advantages over analogous reactions in solution. In acylation reactions of carbon acids, the simultaneous use of a polymeric strong base and a polymeric acylating reagent proved to be superior to the use of soluble reagents, both for bringing about quantitative acylations and for coping with undesirable side reactions. New polymeric strong bases were prepared: polymeric trityllithium, para-substituted trityllithium polymers, and polymeric lithium diisopropylamide. Active esters of polymeric o-nitrophenol and N-1-hydroxybenzotriazole were used as acylation reagents. The scope and limitation of these reactions and their application to general multiphase systems are discussed.
- Cohen,Kraus,Patchornik
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p. 7620 - 7629
(2007/10/02)
-