- Method for synthesizing alkyl olefin through coupling of double-bond carbon-hydrogen bond and saturated carbon-hydrogen bond
-
The invention discloses a method for synthesizing alkyl olefin through coupling of a double-bond carbon-hydrogen bond and a saturated carbon-hydrogen bond. According to to the method, one-pot reactionis implemented on olefin and sulfoxide in the presence of ferric salt and hydrogen peroxide to generate alkyl olefin; in the method, sulfoxide is simultaneously used as a hydrocarbylation reagent anda solvent of olefin, and a reaction product is alkyl olefin from sulfoxide alkyl coupled with olefin carbon atoms, so that an olefin carbon chain is increased; the reaction conditions are mild, the selectivity is good, the yield is high, and industrial production is facilitated.
- -
-
Paragraph 0060-0069; 0092
(2021/02/10)
-
- Method for hydrocarbylation synthesis of trisubstituted and tetrasubstituted olefins from non-terminal olefins
-
The invention discloses a method for hydrocarbylation synthesis of trisubstituted and tetrasubstituted olefins from non-terminal olefins, wherein the method comprises the steps: carrying out hydrocarbylation reaction on the non-terminal olefins and sulfoxide in the presence of ferric salt and hydrogen peroxide, carrying out one-pot reaction on disubstituted non-terminal olefins to generate the trisubstituted olefins, and carrying out one-pot reaction on the trisubstituted non-terminal olefins to generate the tetrasubstituted olefins. In the method, sulfoxide is simultaneously used as a hydrocarbylation reagent and a solvent of olefins, and one more hydrocarbyl substituent is added to a reaction product compared with a double-bond carbon atom of a reactant, so that an olefin carbon chain isincreased; the reaction conditions are mild, the selectivity is good, the yield is high, and industrial production is facilitated.
- -
-
Paragraph 0054-0063; 0070-0072
(2021/02/06)
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- The synergistic copper/ppm Pd-catalyzed hydrocarboxylation of alkynes with formic acid as a CO surrogate as well as a hydrogen source: An alternative indirect utilization of CO2
-
An unprecedented strategy has been developed involving the earth-abundant Cu-catalyzed hydrocarboxylation of alkynes with HCOOH to (E)-acrylic derivatives with high regio- and stereoselectivity via synergistic effects with ppm levels of a Pd catalyst. Both symmetrical and unsymmetrical alkynes bearing various functional groups were successfully hydrocarboxylated with HCOOH, and the modification of a pharmaceutical molecule exemplified the practicability of this process. This protocol employs HCOOH as both a CO surrogate and hydrogen donor with 100% atom economy and it can be viewed as an alternative approach for indirect CO2 utilization. Mechanistic investigations indicate a Cu/ppm Pd cooperative catalysis mechanism via alkenylcopper species as potential intermediates formed from Cu-hydride active catalytic species with HCOOH as a hydrogen source. This bimetallic system involving inexpensive Cu and trace Pd provides a reliable and efficient hydrocarboxylation method to access industrially useful acrylic derivatives with HCOOH as a hydrogen source, and it provides novel clues for optimizing other Cu-H-related co-catalytic systems.
- Chen, Kai-Hong,He, Liang-Nian,Qiu, Li-Qi,Xia, Shu-Mei,Yang, Zhi-Wen,Yao, Xiang-Yang
-
supporting information
p. 8089 - 8095
(2021/11/01)
-
- Direct 3-Acylation of Indolizines by Carboxylic Acids for the Practical Synthesis of Red Light-Releasable Caged Carboxylic Acids
-
To enhance the practicality of photouncaging system using 3-acyl-2-methoxyindolizines, direct acylation of indolizines with carboxylic acids was developed using condensation reagents, generally used for peptide coupling. This method allowed for caging a broad range of carboxylic acids with indolizines. The method enabled a facile synthesis of water-soluble caged bioactive carboxylic acids having an intramolecular photosensitizer. The efficient release of carboxylic acids from the synthesized caged compounds upon red light irradiation was confirmed in neutral buffered solutions.
- Watanabe, Kenji,Terao, Nodoka,Niwa, Takashi,Hosoya, Takamitsu
-
p. 11822 - 11834
(2021/07/31)
-
- Method for preparing alpha, beta-unsaturated carboxylic acid compound
-
The invention discloses a method for preparing an alpha, beta-unsaturated carboxylic acid compound, which comprises the following steps: 1) in an atmosphere containing carbon dioxide, heating and reacting a mixture containing hydrosilane and a copper catalyst to obtain a system I; and 2) adding a raw material containing alkyne and a nickel catalyst into the system I in the step 1), and heating to react. The method has the advantages of simple, easily available, cheap and stable raw materials, common, easily available and stable catalyst, mild reaction conditions, simple post-treatment, high yield and the like.
- -
-
Paragraph 0103-0110; 0511-0518
(2021/05/05)
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- Palladium-Catalyzed Highly Regioselective Hydrocarboxylation of Alkynes with Carbon Dioxide
-
A Pd-catalyzed highly regioselective hydrocarboxylation of alkynes with carbon dioxide has been established. By the combination of Pd(PPh3)4 and 2,2′-bis(diphenylphosphino)-1,1′-binaphthalene (binap), a variety of functionalized alkynes, including aryl alkynes, aliphatic alkynes, propargylamines, and propargyl ethers, could be leveraged to provide a wide array of α-acrylic acids in high yields with high regioselectivity under mild reaction conditions. Experimental and DFT mechanistic studies revealed that this reaction proceeded via the cyclopalladation process of alkynes and carbon dioxide in the presence of binap to generate a five-membered palladalactone intermediate and enabled the formation of Markovnikov adducts. Moreover, this strategy provided an effective method for the late-stage functionalization of alkyne-containing complicated molecules, including natural products and pharmaceuticals.
- Chen, Pengquan,Cheng, Ruixiang,Jiang, Huanfeng,Lei, Ming,Lou, Hongming,Qi, Chaorong,Shi, Fuxing,Wang, Lu,Wu, Wanqing,Xiong, Wenfang,Zhu, Baiyao
-
p. 7968 - 7978
(2020/08/21)
-
- Rhodium(III)-catalyzed β-arylation and- alkenylation of α-trifluoromethylacrylic acid
-
The β-arylation and - alkenylation of trifluoromethylacrylic acid with arylboronic acids and alkenes proceed smoothly under rhodium(III) catalysis. The procedures provide useful synthetic routes from readily available building brocks to β-aryl-α-trifluoromethylpropanoic acid and 5, 5, 5-trifluoro-1, 3-butadiene derivatives. Some of the obtained butadienes exhibit strong fluorescence in the solid state.
- Yoshimoto, Risa,Usuki, Yoshinosuke,Satoh, Tetsuya
-
p. 461 - 464
(2019/06/03)
-
- N-substituted acrylamide derivatives as DHODH inhibitors and preparation and use of N-substituted acrylamide derivatives
-
The invention relates to N-substituted acrylamide derivatives as DHODH inhibitors and preparation and use of the N-substituted acrylamide derivatives. In particular, the invention discloses a compoundshown in a general formula I and the preparation and use of the compound. The compound has excellent DHODH inhibitory activation, so the compound can be used for treating or preventing various diseases caused by DHODH, the various diseases include but not limited to cancer, rheumatoid arthritis, lupus erythematosus, organ transplant rejection and other autoimmune diseases, and colitis, rhinitis and other inflammatory diseases.
- -
-
Paragraph 0178-0179; 00181
(2019/11/04)
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- A Highly Efficient NHC-Catalyzed Aerobic Oxidation of Aldehydes to Carboxylic Acids
-
An N-heterocyclic carbene (NHC) organocatalytic aerobic oxidation of aldehydes to the corresponding carboxylic acids is explored. Remarkably, this method allows for efficient conversion of different classes of aldehydes including highly challenging electron-rich aryl aldehydes, ortho -substituted aryl aldehydes, various heteroaromatic aldehydes and α,β-unsaturated aldehydes under mild reaction conditions. These substrates, under previously reported NHC-catalyzed methods, are typically unreactive or give poor yields, require high reaction temperatures and reaction times of several days.
- Khatana, Anil Kumar,Singh, Vikram,Gupta, Manoj Kumar,Tiwari, Bhoopendra
-
p. 4290 - 4294
(2018/11/23)
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- Visible-Light-Driven alkyne hydro-/carbocarboxylation using CO2 via iridium/cobalt dual catalysis for divergent heterocycle synthesis
-
We present herein the first visible-light-driven hydrocarboxylation as well as carbocarboxylation of alkynes using CO2 via an iridium/cobalt dual catalysis. Such transformations provide access to various pharmaceutically important heterocycles in a one-pot procedure from readily available alkynes. Coumarins, 2-quinolones, and 2-benzoxepinones were directly accessed through a one-pot alkyne hydrocarboxylation/alkene isomerization/cyclization sequence in which the Ir photocatalyst serves a dual role to promote single-electron transfer in alkyne hydrocarboxylation and energy transfer in the subsequent alkene isomerization. Moreover, an unprecedented cobalt carboxylation/acyl migration cascade enables alkyne difunctionalization to introduce γ-hydroxybutenolides with high efficiency. We expect that this cascade strategy will inspire new perspectives for alkyne and alkene difunctionalization.
- Hou, Jing,Ee, Aloysius,Feng, Wei,Xu, Jin-Hui,Zhao, Yu,Wu, Jie
-
supporting information
p. 5257 - 5263
(2018/04/24)
-
- Visible-light-enabled denitrative carboxylation of β-nitrostyrenes: A direct photocatalytic approach to cinnamic acids
-
The first workable application of β-nitrostyrenes and CBr4 as coupling partners for a highly stereoselective synthesis of (E)-cinnamic acids under visible light photoredox catalysis is reported. The reaction involves a radical denitrative tribromomethylation/hydrolysis cascade to afford (E)-cinnamic acids in excellent yields at room temperature in a one-pot procedure. Moreover, the implementation of visible light as a clean and inexpensive energy source and CBr4 as the latent source of carboxylic groups makes the protocol reconcilable with the present day scenario of organic synthesis.
- Tripathi, Shubhangi,Yadav, Lal Dhar S.
-
supporting information
p. 3765 - 3769
(2018/03/06)
-
- Macrolide Synthesis through Intramolecular Oxidative Cross-Coupling of Alkenes
-
A RhIII-catalyzed intramolecular oxidative cross-coupling between double bonds for the synthesis of macrolides is described. Under the optimized reaction conditions, macrocycles containing a diene moiety can be formed in reasonable yields and with excellent chemo- and stereoselectivity. This method provides an efficient approach to synthesize macrocyclic compounds containing a 1,3-conjugated diene structure.
- Jiang, Bing,Zhao, Meng,Li, Shu-Sen,Xu, Yun-He,Loh, Teck-Peng
-
supporting information
p. 555 - 559
(2018/02/21)
-
- Carboxylation of styrenes with CBr4 and DMSO via cooperative photoredox and cobalt catalysis
-
Cooperative photoredox and cobalt catalyzed carboxylation of styrenes with CBr4 to afford the corresponding α,β-unsaturated carboxylic acids has been realized through radical addition and Kornblum (DMSO) oxidation. DMSO serves as the oxidant, oxygen source and solvent under these photocatalytic conditions.
- Song, Cai-Xia,Chen, Ping,Tang, Yu
-
p. 11233 - 11243
(2017/02/26)
-
- Cp2TiCl2-catalyzed hydrocarboxylation of alkynes with CO2: formation of α,β-unsaturated carboxylic acids
-
Cp2TiCl2-catalyzed hydrocarboxylation of alkynes with CO2 (atmospheric pressure) has been reported. A range of alkynes were transformed to the corresponding α,β-unsaturated carboxylic acids in high yields with high regioselectivity. The reaction proceeded with hydrotitanation, transmetalation, and subsequently carboxylation with CO2
- Shao, Peng,Wang, Sheng,Du, Gaixia,Xi, Chanjuan
-
p. 3534 - 3539
(2017/01/25)
-
- Synthesis of Albicidin Derivatives: Assessing the Role of N-terminal Acylation on the Antibacterial Activity
-
The peptide antibiotic albicidin, which is synthesized by the plant pathogenic bacterium, Xanthomonas albilineans, represents the most prominent member of a new class of antibacterial gyrase inhibitors. It shows remarkable antibacterial activities against Gram-positive and Gram-negative microorganisms. Its unique structure potentially represents a new lead structure for the development of an antibacterial drug. Here we report the synthesis of 14 albicidin derivatives with structural variations at the N-terminus, primarily investigating the effects of variation of cinnamoyl, phenylpropanoyl, and benzoyl residues. Gyrase inhibition in vitro and determination of minimal inhibitory concentrations were assessed in parallel. Activities in a nanomolar range and the importance of N-acylation were demonstrated.
- Kerwat, Dennis,Gr?tz, Stefan,Kretz, Julian,Seidel, Maria,Kunert, Maria,Weston, John B.,Süssmuth, Roderich D.
-
supporting information
p. 1899 - 1903
(2016/10/12)
-
- Ni-Catalyzed Regioselective Hydrocarboxylation of Alkynes with CO2 by Using Simple Alcohols as Proton Sources
-
A mild and user-friendly Ni-catalyzed regioselective hydrocarboxylation of alkynes with CO2 (1 bar) is described. This protocol is characterized by a wide scope while obviating the need for sensitive organometallic species and by an unprecedented regioselectivity pattern using simple alcohols as proton sources.
- Wang, Xueqiang,Nakajima, Masaki,Martin, Ruben
-
supporting information
p. 8924 - 8927
(2015/08/03)
-
- Highly efficient Rh-catalyzed asymmetric hydrogenation of α,β-unsaturated nitriles
-
A highly efficient enantioselective hydrogenation of α,β-unsaturated nitriles catalyzed by Rh-(R,R)-f-spiroPhos complex has been developed. With Rh-(R,R)-f-spiroPhos catalyst and under mild conditions, a wide range of α,β-unsaturated nitriles including the (E)- and (Z)-isomers of 3-alkyl-3-aryl, 3,3-diaryl, and 3,3-dialkyl α,β-unsaturated nitriles were hydrogenated to the corresponding chiral nitriles with excellent enantioselectivities (up to 99.9% ee) and high turnover numbers (TON up to 10,000).
- Yan, Qiaozhi,Kong, Duanyang,Li, Meina,Hou, Guohua,Zi, Guofu
-
supporting information
p. 10177 - 10181
(2015/09/01)
-
- Key structural features of cis-cinnamic acid as an allelochemical
-
1-O-cis-cinnamoyl-β-d-glucopyranose is one of the most potent allelochemicals isolated from Spiraea thunbergii Sieb. It is suggested that it derives its strong inhibitory activity from cis-cinnamic acid, which is crucial for phytotoxicity. It was synthesized to confirm its structure and bioactivity, and also a series of cis-cinnamic acid analogues were prepared to elucidate the key features of cis-cinnamic acid for lettuce root growth inhibition. The cis-cyclopropyl analogue showed potent inhibitory activity while the saturated and alkyne analogues proved to be inactive, demonstrating the importance of the cis-double bond. Moreover, the aromatic ring could not be replaced with a saturated ring. However, the 1,3-dienylcyclohexene analogue showed strong activity. These results suggest that the geometry of the C-C double bond between the carboxyl group and the aromatic ring is essential for potent inhibitory activity. In addition, using several light sources, the photostability of the cinnamic acid derivatives and the role of the C-C double bond were also investigated.
- Abe, Masato,Nishikawa, Keisuke,Okuda, Katsuhiro,Shindo, Mitsuru,Fukuda, Hiroshi,Nakanishi, Kazunari,Tazawa, Yuta,Taniguchi, Tomoya,Park, So-Young,Hiradate, Syuntaro,Fujii, Yoshiharu
-
p. 56 - 67,12
(2012/12/12)
-
- Microwave-assisted synthesis of the (E)-α-methylalkenoate framework from multifunctionalized allylic phosphonium salts
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A convenient and general microwave-assisted method for the synthesis of stereochemically defined α-methylalkenoic acids and esters from allylic phosphonium salts in a basic aqueous medium is described. A selective preparation of acids or esters was dependent on the base (NaOH or NaHCO 3) employed in the reaction and could be achieved with good to excellent yields under mild conditions in the absence of hydrides and reducing agents.
- Meier, Lidiane,Ferreira, Misael,Sa, Marcus M.
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experimental part
p. 179 - 186
(2012/07/14)
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- Palladium-catalyzed fluoride-free cross-coupling of intramolecularly activated alkenylsilanes and alkenylgermanes: Synthesis of tamoxifen as a synthetic application
-
We have demonstrated that intramolecular hypercoordination of a carboxylic acid is a powerful activation strategy for the palladium-catalyzed cross-coupling reaction of trialkyl(vinyl)silanes and trialkyl(vinyl)germanes under fluoride-free conditions. Z-β-Trialkylsilyl- and Z-β- trialkylgermylacrylic acids, synthesized stereoselectively by olefination with ynolates, are highly stable and useful reagents for cross-coupling with a variety of aryl iodides to provide tetrasubstituted olefins possessing different carbon substituents in a stereocontrolled and diversity-oriented manner. An application to a stereoselective synthesis of (Z)-tamoxifen is also reported. Copyright
- Matsumoto, Kenji,Shindo, Mitsuru
-
p. 642 - 650
(2012/05/04)
-
- Stereoselective synthesis of α,β-unsaturated carboxylic acids from alkynes using the Fe(CO)5/t-BuOK/AcOH/CH2Cl 2 reagent system
-
Reactive iron carbonyl species generated in situ using the Fe(CO) 5/t-BuOK/CH3COOH/CH2Cl2 reagent system reacts with alkynes to give the corresponding α,β-unsaturated carboxylic acids after CuCl2·2H2O oxidation with some regio and stereoselectivity.
- Beesu, Mallesh,Periasamy, Mariappan
-
experimental part
p. 30 - 33
(2012/04/17)
-
- Highly regio- and stereoselective three-component nickel-catalyzed syn-hydrocarboxylation of alkynes with diethyl zinc and carbon dioxide
-
Hydrocarboxylation of alkynes: The first example of nickel-catalyzed hydrozincation of alkynes that form stereodefined hydrocarboxylation products is presented (see scheme; cod=cycloocta-1,5-diene). This catalytic system is efficient for the activation of CO2 and the three-component reaction produces products that could be converted into important oxindole or γ-butyrolactam derivatives. Copyright
- Li, Suhua,Yuan, Weiming,Ma, Shengming
-
supporting information; experimental part
p. 2578 - 2582
(2011/05/03)
-
- Copper-catalyzed hydrocarboxylation of alkynes using carbon dioxide and hydrosilanes
-
Getting a fix: The copper-catalyzed hydrocarboxylation of alkynes using carbon dioxide in the presence of a hydrosilane, which serves as a reducing agent, has been developed (see scheme). Copper fluorides bearing N-heterocyclic carbene ligands such as IMes and Cl2IPr show high catalytic activities.
- Fujihara, Tetsuaki,Xu, Tinghua,Semba, Kazuhiko,Terao, Jun,Tsuji, Yasushi
-
supporting information; experimental part
p. 523 - 527
(2011/03/16)
-
- Pd/C and NaBH4 in basic aqueous alcohol: An efficient system for an environmentally benign oxidation of alcohols
-
We report the oxidation of a wide range of alcohols using an environmentally benign and economical process. The use of Pd/C heterogeneous catalysts along with NaBH4in aqueous ethanol or methanol and either K2CO3 or KOH as base at room temperature under molecular oxygen or air give the corresponding oxidation products. This protocol is versatile since it is capable of oxidizing alcohols to its desired carbonyl or carboxyl counterpart. Room temperature reaction in aqueous system and recyclability of the catalyst are among the advantages of this manipulation. These advantages make the process safe and cheaper rendering it favorable from both economic and environmental viewpoints. Georg Thieme Verlag Stuttgart New York.
- An, Gwangil,Ahn, Hyunseok,De Castro, Kathlia A.,Rhee, Hakjune
-
experimental part
p. 477 - 485
(2010/06/13)
-
- Stereoselective olefination reactions promoted by Rieke manganese
-
A study of the advantages of using manganese, an inexpensive and nontoxic metal, to perform stereoselective β-elimination reactions and to promote sequential olefination reactions of aldehydes to obtain α,β- unsaturated esters and amides is presented. Various elimination reactions, all of them characterized by occurring with complete stereoselectivity and in high yields, were performed using active manganese (Mn*) as metalating agent. This ability of manganese has been applied to develop a novel and direct synthesis of (E)-α,β-unsaturated esters or amides and (Z)-α,β-unsaturated α-halo esters and α-choroamides through a Mn*-mediated sequential olefination protocol of aldehydes with dichloro esters or amides and trihalo esters or trichloroamides, respectively. Georg Thieme Verlag Stuttgart.
- Concellon, Jose M.,Rodriguez-Solla, Humberto,Del Amo, Vicente,Diaz, Pamela
-
experimental part
p. 2634 - 2645
(2009/12/06)
-
- Correlation of hydrolysis and desilylation of 2-[(trimethylsilyl)methyl] acrylate derivatives in aqueous alkali solutions
-
Hydrolysis and desilylation reaction of 2-[(trimethylsilyl)methyl]acrylate (=2-[(trimethylsilyl)methyl] prop-2-enoate) derivatives were studied to evaluate the effect of the presence/absence of a further conjugating substituent (Schemes 3 and 4 and Tables 1 and 2). The substrates having a nonconjugating substituent at the acrylate moiety were stable to dilute alkali conditions, and afforded simple hydrolysis products under concentrated alkali conditions. In contrast, both hydrolysis and desilylation occurred from the substrates bearing conjugated substituents at the acrylate skeleton. The difference in reactivity can be explained in terms of the stabilization of the intermediate anion.
- Kuroda, Chiaki,Sunakawa, Takeshi,Muguruma, Yuichi
-
scheme or table
p. 888 - 896
(2009/03/11)
-
- Environmentally benign oxidation reaction of aldehydes to their corresponding carboxylic acids using Pd/C with NaBH4 and KOH
-
Pd/C catalyst in aqueous methanol with sodium borohydride and potassium hydroxide under the air efficiently oxidized aldehydes to their corresponding carboxylic acids at room temperature. The utilization of room temperature reaction, aqueous methanol solvent, and the open-air conditions make this manipulation very interesting for economic and environmental perspectives.
- Lim, Minkyung,Yoon, Cheol Min,An, Gwangil,Rhee, Hakjune
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p. 3835 - 3839
(2008/02/07)
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- Sequential reactions promoted by manganese: Completely stereoselective synthesis of (E)-α,β-unsaturated amides, ketones, aldehydes, and carboxylic acids
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(Chemical Equation Presented) A complete E-selective synthesis of α,β-unsaturated amides through a sequential reaction of a range of dichloroamides with a variety of aldehydes promoted by Rieke manganese (Mn*) is reported. A mechanism based on a sequential aldol-type reaction and a completely stereoselective β-elimination is proposed to explain these results. The unsaturated amides obtained are readily and efficiently transformed into α,β-unsaturated ketones, aldehydes, or carboxylic acids without loss of the diastereoisomeric purity of the C-C double bond.
- Concellon, Jose M.,Rodriguez-Solla, Humberto,Diaz, Pamela
-
p. 7974 - 7979
(2008/02/13)
-
- A facile one-pot stereoselective synthesis of trisubstituted (E)-2-methylalk-2-enoic acids from unactivated Baylis-Hillman adducts and a simple access to some important insect pheromones
-
An efficient one-pot stereoselective synthesis of trisubstituted (E)-2-methylalk-2-enoic acids has been accomplished by treatment of unactivated Baylis-Hillman adducts, 3-hydroxy-2-methylenealkanoates, with Al-NiCl2·6H2O in methanol at room temperature followed by hydrolysis. The method has been applied to the synthesis of three important insect pheromones, (4S,2E)-2,4-dimethyl-2-hexenoic acid, (+)-(S)-manicone and (+)-(S)-normanicone.
- Das, Biswanath,Chowdhury, Nikhil,Banerjee, Joydeep,Majhi, Anjoy
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p. 6615 - 6618
(2007/10/03)
-
- Synthetic applications of Baylis-Hillman chemistry: An efficient and solely stereoselective synthesis of (E)-α-methylcinnamic acids and potent hypolipidemic agent LK-903 from unmodified Baylis-Hillman adducts
-
An efficient and solely stereoselective synthesis of (E)-α- methylcinnamic acids has been accomplished in single pot by reduction of the unmodified Baylis-Hillman adducts, methyl-3-hydroxy-3-aryl-2- methylenepropanoates with I2/NaBH4 reagent system at room temperature followed by hydrolysis. The efficacy of this method has been proved in the total synthesis of 1-[p-(myristyloxy)-α-methylcinnamoyl]glycerol, LK-903, a highly active hypolipidemic agent.
- Das, Biswanath,Banerjee, Joydeep,Chowdhury, Nikhil,Majhi, Anjoy
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p. 1725 - 1727
(2007/10/03)
-
- Stereoselective synthesis of (E)-trisubstituted α,β-unsaturated amides and acids
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Potassium alkoxides of N-acyl-oxazolidin-2-one-syn-aldols undergo stereoselective elimination reactions to afford a range of trisubstituted (E)-αβ-unsaturated amides in >95% de, that may be subsequently converted into their corresponding (E)-αβ-unsaturated acids or (E)-αβ-unsaturated oxazolines in good yield. syn-Aldols derived from αβ-unsaturated aldehydes gave their corresponding trisubstituted (E)-αβ-unsaturated-amides with poorer levels of diastereocontrol, whilst there was a similar loss in (E)-selectivity during elimination of syn-aldols derived from chiral aldehydes. These elimination reactions proceed via rearrangement of the potassium alkoxide of the syn-aldol to a 1,3-oxazinane-2,4-dione enolate intermediate that subsequently eliminates carbon dioxide to afford a trisubstituted (E)-αβ-unsaturated amide. The (E)-selectivity observed during the ElcB-type elimination step has been rationalised using a simple conformational model that employs a chair-like transition state to explain the observed stereocontrol. The Royal Society of Chemistry 2005.
- Feuillet, Fred J. P.,Cheeseman, Matt,Mahon, Mary F.,Bull, Steven D.
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p. 2976 - 2989
(2007/10/03)
-
- Microbial deracemization of α-substituted carboxylic acids: Control of the reaction path
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A novel approach to preparing optically active α-substituted carboxylic acids using the whole cells of Nocardia diaphanozonaria JCM 3208 is described. When 2-phenylthiopropanoic acid and 2-methyl-3-phenylpropanoic acid were subjected to the reaction under aerobic conditions, the oxidation reaction proceeded preferentially rather than deracemization of these substrates. Herein, we report the design of reaction conditions to increase the deracemization activity in preference to oxidation reactions. In addition, we have successfully detected a metabolic intermediate in the reaction mixture of 2-methyl-3-phenylpropanoic acid, which indicates that the deracemization is a competitive reaction against the α-oxidation pathway of fatty acid metabolism.
- Kato, Dai-Ichiro,Miyamoto, Kenji,Ohta, Hiromichi
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p. 2965 - 2973
(2007/10/03)
-
- An (E)-selective synthesis of trisubstituted (E)-α, β-unsaturated acid derivatives
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Potassium alkoxides of N-acyloxazolidin-2-one derived synaldolates undergo a novel tandem intramolecular cyclisation elimination reaction to afford trisubstituted (E)-α,β-unsaturated amides in high d.e., which may be converted into their corresponding acids or oxazolines in good yield.
- Feuillet, Fred J. P.,Robinson, Diane E. J. E.,Bull, Steven D.
-
p. 2184 - 2185
(2007/10/03)
-
- Tungsten(0) alkylidene complexes stabilized as pyridinium ylides: New aspects of their synthesis and reactivity
-
The interaction of dihydropyridines with alkoxycarbene complexes of tungsten has been shown to lead to pyridinium ylid complexes: this transformation has now been applied to the synthesis of a hydroxyl-containing ylid complex by ring-opening of the pentacarbonyl (2-oxacyclopentylidene) tungsten(0) complex and to the synthesis of a series of chiral ylid complexes both from chiral and non-chiral carbene complexes by the use of dihydropyridines and dihydronicotines, respectively. The transfer of the alkylidene moiety of these complexes to nucleophilic olefins will be outlined and discussed. Especially relevant is the interaction of these pyridinium ylid complexes with unsaturated substrates such as dihydropyridines, enamines, and β-alkoxy bis(trimethyl-silyl) ketene acetals. This latter reaction leads to conjugated carboxylic acids, and has been be applied to a new synthesis of a honey bee pheromone, the queen substance.
- Rudler, Henri,Durand-Réville, Thomas
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p. 571 - 587
(2007/10/03)
-
- Highly E-selective synthesis of α,β-unsaturated amides from N-2- methoxyphenyl aldimines via lithium ynolates
-
Lithium ynolates reacted with N-2-methoxyphenyl (OMP) aldimines to afford α,β-unsaturated amides in excellent E-selectivity via a retro- Mannich reaction of the 2:1 adducts (β-lactams), followed by cleavage of the β-lactam enolates. (C) 2000 Elsevier Science Ltd.
- Shindo, Mitsuru,Oya, Soichiro,Murakami, Ryoko,Sato, Yusuke,Shishido, Kozo
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p. 5947 - 5950
(2007/10/03)
-
- A facile one-pot conversion of acetates of the Baylis-Hillman adducts to [E]-α-methylcinnamic acids
-
A simple and convenient stereoselective synthesis of [E]-α- methylcinnamic acids via the nucleophilic addition of hydride ion from sodium borohydride to methyl 3-acetoxy-3-aryl-2-methylenepropanoates followed by hydrolysis and crystallization is described
- Basavaiah,Krishnamacharyulu,Hyma,Sarma,Kumaragurubaran
-
p. 1197 - 1200
(2007/10/03)
-
- Lewis acid promoted hetero [2 + 2] cycloaddition reactions of aldehydes with 10-propynyl-9(10h)-acridone. A highly stereoselective synthesis of acrylic acid derivatives and 1,3-dienes using an electron deficient variant of ynamine
-
(matrix presented) Reactivities of 10-propynyl-9(10H)-acridone toward various aldehydes in BF3·Et20-promoted hetero [2 + 2] cycloaddition reactions are described here. This electron deficient variant of ynamine is more stable and eas
- Hsung, Richard P.,Zificsak, Craig A.,Wei, Lin-Li,Douglas, Christopher J.,Xiong, Hui,Mulder, Jason A.
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p. 1237 - 1240
(2008/02/09)
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- Reactivity of substituted and unsubstituted diphenylphosphonium diylides towards carbonic acids derivatives
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In order to further delimit the scope of application of diphenylphosphonium diylides, their reactivity towards carbonic acid derivatives was investigated. Non-stabilized diylides react with ethyl carbonate to give new monoylide intermediates which lead, by in situ Wittig reaction with carbonyl compounds, to the synthesis of α,β-unsaturated esters or acids the double bond being di- or trisubstituted. The reaction proceeds in mild conditions and with high E stereoselectivity. Stabilized diylides are inactive towards carbonates but semi-stabilized diylides react with ethyl carbonate leading to the synthesis of non-functionalized alkenes instead of the α,β-unsaturated esters or acids.
- Cristau,Taillefer
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p. 1507 - 1522
(2007/10/03)
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- α-LITHIOALKYLPHOSPHONATES AS FUNCTIONAL GROUP CARRIERS. PART II. A DIRECT (E)-CINNAMIC AND 2-ALKYL-CINNAMIC ACIDS SYNTHESIS.
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Sequential treatment of α-lithioalkylphosphonates with tert-butyl fluoroformate or di-tert-butyl dicarbonate and an aromatic aldehyde gives tert-butyl acrylic esters convertible into acrylic acids by protolysis with trifluoroacetic acid.
- Teulade, Marie-Paule,Savignac, Philippe,About-Jaudet, Elie,Collignon, Nooel
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- Nickel-catalyzed reductive electrocarboxylation of disubstituted alkynes
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Electrochemically reduced (Ni(bpy)3(BF4)2 catalyzes the reaction of carbon dioxide with disubstituted alkynes to yield mono-and di-carboxylated derivatives.The reaction is performed under mild conditions in an undivided cell fitted with a sacrificial magnesium anode.
- Dunach, Elisabet,Derien, Sylvie,Perichon, Jacques
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p. C33 - C36
(2007/10/02)
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- Conformational Analysis of 1,1,2-Trisubstituted Ethanes by PMR: Part I - 3-Aryl-2-methylpropanols
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A self-consistent model for the conformational analysis of 1,1,2-trisubstituted ethanes is developed, based on the temperature dependence of vicinal proton-proton coupling constants.Synthesis of racemates of 2(R), 3(S)- and 2(S), 3(R)-2,3-dideutero-2-methyl-3-phenyl-1-propanols is accomplished using known reactions of well-defined stereochemistry.By comparing the PMR spectra of undeuterated and deuterated compounds, an unequivocal assignment of benzylic protons is made.Concentration and variable-temperature studies have revealed the existence of very weak intramolecular interaction in three alcohols, p-R-C6H4-CH2-CHMe-CH2-OH, where R = NO2, H and OMe.
- Somasekharan, K. N.,Kiefer, Edgar F.
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- Organic Syntheses via Transition Metal Complexes, 19. - β-Methylenecyclopentenones via Iron Carbonyl-Induced Cycloaddition of Alkynes to Allenes and Carbon Monoxide
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From alkynes, allenes, and carbon monoxide β-methylenecyclopentenones 3 and 4 are obtained in a one-pot procedure.The reaction involves a template-induced cycloaddition via carbonyl iron complexes as intermediates.The regio- and stereoselectivity of this synthesis has been studied by means of model reactions.The fragmentation pattern observed in the mass spectrum of these compounds corresponds to the retro-synthesis.
- Aumann, Rudolf,Weidenhaupt, Hermann-Josef
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- HIGHLY DIASTEREOSELECTIVE TANDEM ALKYLATION OF ACYCLIC α,β-UNSATURATED ESTERS BASED ON THE NOVEL USE OF DITHIOACETAL UNIT
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Highly diastereoselective tandem alkylation process of acyclic α,β-unsaturated esters was developed based on the novel use of dithioacetal as a stereocontrolling unit.
- Kawasaki, Hisashi,Tomioka, Kiyoshi,Koga, Kenji
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p. 3031 - 3034
(2007/10/02)
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- Phosphite-Mediated in Situ Carboxyvinylation: A New General Acrylic Acid Synthesis
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Sequential treatment of a 2-halo carboxylic acid with a dialkyl phosphite and an aldehyde or ketone in the presence of 3 equiv of sodium hydride in glyme constitutes a new general acrylic acid synthesis superior to conventional methods.An alkoxide-in-alcohol variant may be used with bromo- or chloroacetic acid and aryl aldehydes to produce cinnamic acids conveniently.The scope and other features of the synthesis are discussed.
- Brittelli, David R.
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p. 2514 - 2520
(2007/10/02)
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- Ring-Opening Reactions of Anionic Cyclopropyl Compounds. 3
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The reaction of KO-t-Bu in Me2SO with the tricyclocyclopropyl carbonyl compounds 3a,b was shown to result in the formation of cyclopentadienes and cinnamic acid derivatives 4a,b and 5a,b which were shown to be preceded by intermediates 6a,b.It is suggested that 6a,b rearrange to 4a,b and 5a,b via an unusual electrocyclization followed by a fragmentation.An example of an apparent conrotatory ring opening of a cyclopropyl carbanion or anion radical is presented in the conversion of 8 to 9.
- Brand, Richard A.,Mulvaney, J. E.
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p. 633 - 636
(2007/10/02)
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- Indaneacetic acid derivatives
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This invention provides new compounds of formula I, STR1 wherein R1 is lower alkyl, R2 is hydrogen or lower alkyl, R3 is hydrogen or lower alkyl, R4 is hydrogen or lower alkyl, R5 is hydrogen, chlorine or lower alkyl, and each of R6 and R7 is hydrogen, or, when R5 is hydrogen, R6 may also be chlorine or lower alkyl, and R7 chlorine or lower alkyl, Useful as anti-phlogistic and anti-arthritic agents.
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