- Photoredox Activation of Formate Salts: Hydrocarboxylation of Alkenes via Carboxyl Group Transfer
-
A photoredox activation mode of formate salts for carboxylation was developed. Using a formate salt as the reductant, carbonyl source, and hydrogen atom transfer reagent, a wide range of alkenes can be converted into acid products via a carboxyl group tra
- Huang, Yan,Hou, Jing,Zhan, Le-Wu,Zhang, Qian,Tang, Wan-Ying,Li, Bin-Dong
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p. 15004 - 15012
(2021/12/14)
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- Exploring the synthetic potential of a marine transaminase including discrimination at a remote stereocentre
-
The marine transaminase, P-ω-TA, can be employed for the transamination from 1-aminotetralins and 1-aminoindanes with differentiation of stereochemistry at both the site of reaction and at a remote stereocentre resulting in formation of ketone products with up to 93% ee. While 4-substituents are tolerated on the tetralin core, the presence of 3- or 8-substituents is not tolerated by the transaminase. In general P-ω-TA shows capacity for remote diastereoselectivity, although both the stereoselectivity and efficiency are dependent on the specific substrate structure. Optimum efficiency and selectivity are seen with 4-haloaryl-1-aminotetralins and 3-haloaryl-1-aminoindanes, which may be associated with the marine origin of this enzyme. This journal is
- Schwarz, Maria,Murphy, Edel J.,Foley, Aoife M.,Woods, David F.,Castilla, Ignacio Abreu,Reen, F. Jerry,Collins, Stuart G.,O'gara, Fergal,Maguire, Anita R.
-
p. 188 - 198
(2021/01/18)
-
- Covalent organic framework supported Pd(II)-catalyzed conjugate additions of arylboronic acids to α,β-unsaturated carboxylic acids
-
A palladium(II)-coordinated covalent organic framework (Pd(II)@COF) was mechanochemically synthesized from [2,2′-bipyridine]-5,5′-diamine (Bpy) and 1,3,5-triformylphloroglucinol (Tp), which was demonstrated as a catalyst for conjugate addition of arylboronic acids to unreactive α,β-unsaturated carboxylic acids in aqueous media (water/acetone = 1:1). Modest to good yields were obtained for most substrates, and studies on the catalyst recyclability showed that the heterogeneous catalyst gave >80% yields in the first 4 cycles. This research broadens the application of COFs supported catalysis and gave a new option for Pd(II)-catalysis.
- Wen, Min,Lu, Shujuan,Fan, Chaogang,Shen, Kai,Lin, Shaohui,Pan, Qinmin
-
-
- Ruthenium-catalyzed intramolecular arene C(sp2)-H amidation for synthesis of 3,4-dihydroquinolin-2(1 H)-ones
-
We report the [Ru(p-cymene)(l-proline)Cl] ([Ru1])-catalyzed cyclization of 1,4,2-dioxazol-5-ones to form dihydroquinoline-2-ones in excellent yields with excellent regioselectivity via a formal intramolecular arene C(sp2)-H amidation. The reactions of the 2- and 4-substituted aryl dioxazolones proceeds initially through spirolactamization via electrophilic amidation at the arene site, which is para or ortho to the substituent. A Hammett correlation study showed that the spirolactamization is likely to occur by electrophilic nitrenoid attack at the arene, which is characterized by a negative ρ value of -0.73.
- Au, Chi-Ming,Ling, Cho-Hon,Sun, Wenlong,Yu, Wing-Yiu
-
supporting information
p. 3310 - 3314
(2021/05/29)
-
- Harnessing Applied Potential: Selective β-Hydrocarboxylation of Substituted Olefins
-
The construction of carboxylic acid compounds in a selective fashion from low value materials such as alkenes remains a long-standing challenge to synthetic chemists. In particular, β-addition to styrenes is underdeveloped. Herein we report a new electrosynthetic approach to the selective hydrocarboxylation of alkenes that overcomes the limitations of current transition metal and photochemical approaches. The reported method allows unprecedented direct access to carboxylic acids derived from β,β-trisubstituted alkenes, in a highly regioselective manner.
- Alkayal, Anas,Buckley, Benjamin R.,Malkov, Andrei V.,Montanaro, Stephanie,Tabas, Volodymyr,Wright, Iain A.
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supporting information
(2020/02/13)
-
- Synergistic N-Heterocyclic Carbene/Palladium-Catalyzed Umpolung 1,4-Addition of Aryl Iodides to Enals
-
An umpolung 1,4-addition of aryl iodides to enals promoted by cooperative (terpy)Pd/NHC catalysis was developed that generates various bioactive β,β-diaryl propanoate derivatives. This system is not only the first reported palladium-catalyzed arylation of NHC-bound homoenolates but also expands the scope of NHC-induced umpolung transformations. A diverse array of functional groups such as esters, nitriles, alcohols, and heterocycles are tolerated under the mild conditions. This method also circumvents the use of moisture-sensitive organometallic reagents.
- Yang, Wenjun,Ling, Bo,Hu, Bowen,Yin, Haolin,Mao, Jianyou,Walsh, Patrick J.
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p. 161 - 166
(2019/12/03)
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- Exploration of New Biomass-Derived Solvents: Application to Carboxylation Reactions
-
A range of hitherto unexplored biomass-derived chemicals have been evaluated as new sustainable solvents for a large variety of CO2-based carboxylation reactions. Known biomass-derived solvents (biosolvents) are also included in the study and the results are compared with commonly used solvents for the reactions. Biosolvents can be efficiently applied in a variety of carboxylation reactions, such as Cu-catalyzed carboxylation of organoboranes and organoboronates, metal-catalyzed hydrocarboxylation, borocarboxylation, and other related reactions. For many of these reactions, the use of biosolvents provides comparable or better yields than the commonly used solvents. The best biosolvents identified are the so far unexplored candidates isosorbide dimethyl ether, acetaldehyde diethyl acetal, rose oxide, and eucalyptol, alongside the known biosolvent 2-methyltetrahydrofuran. This strategy was used for the synthesis of the commercial drugs Fenoprofen and Flurbiprofen.
- Gevorgyan, Ashot,Hopmann, Kathrin H.,Bayer, Annette
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p. 2080 - 2088
(2020/02/20)
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- Visible-Light-Driven Reductive Carboarylation of Styrenes with CO2 and Aryl Halides
-
The first example of visible-light-driven reductive carboarylation of styrenes with CO2 and aryl halides in a regioselective manner has been achieved. A broad range of aryl iodides and bromides were compatible with this reaction. Moreover, pyridyl halides, alkyl halides, and even aryl chlorides were also viable with this method. These findings may stimulate the exploration of novel visible-light-driven Meerwein arylation-addition reactions with user-friendly aryl halides as the radical sources and the photocatalytic utilization of CO2
- Gao, Yuzhen,Li, Gang,Wang, Hao,Zhou, Chunlin
-
supporting information
p. 8122 - 8129
(2020/05/20)
-
- Synthesis method of succinic acid derivative or 3 -arylpropionic acid (by machine translation)
-
The invention discloses a synthesis method of a succinic acid derivative or 3 -arylpropionic acid, which comprises the following steps: adding a base in a drying reaction tube and CO removing CO. 2 The reaction is carried out under the irradiation of visible light, the reaction is carried out under visible light irradiation, and then separation and purification are carried out to obtain the butanedioic acid derivative or 3 -arylpropionic acid product; the base comprises sodium tert-butoxide, potassium tert-butoxide, lithium tert-butyl alcohol and 4 - potassium carbonate; and the reaction substrate comprises an acrylate compound or an aryl vinyl compound. CO can be induced by visible light. 2 The scheme provided by the invention is mild in reaction condition and wide in reaction 3 - substrate selectivity, and the reaction substrate is wide in selectivity, the raw materials are cheap and easily available, and the method has a good industrial application prospect. (by machine translation)
- -
-
Paragraph 0101-0114; 0115; 0144
(2020/10/30)
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- Construction of enantioenriched 9H-Fluorene frameworks via a cascade reaction involving remote vinylogous dynamic kinetic resolution
-
The benzylic C-H group of α,α-dicyanoolefins from 3-substituted 1-indanones could be significantly activated via transmission along the aromatic system, thus enabling dynamic kinetic resolution via a traditional reversible deprotonation- protonation process. Enantioenriched 9-substituted 9H-fluorene frameworks were finally constructed through an asymmetric vinylogous Michael addition to nitroolefins, followed by a cascade cyclization and oxidative aromatization process, under the catalysis of a chiral bifunctional thiourea-tertiary amine.
- Hu, Cui-Xia,Chen, Lin,Hu, Di,Song, Xue,Chen, Zhi-Chao,Du, Wei,Chen, Ying-Chun
-
supporting information
p. 8973 - 8977
(2020/11/30)
-
- Synthesis of Carboxylic Acids by Palladium-Catalyzed Hydroxycarbonylation
-
The synthesis of carboxylic acids is of fundamental importance in the chemical industry and the corresponding products find numerous applications for polymers, cosmetics, pharmaceuticals, agrochemicals, and other manufactured chemicals. Although hydroxycarbonylations of olefins have been known for more than 60 years, currently known catalyst systems for this transformation do not fulfill industrial requirements, for example, stability. Presented herein for the first time is an aqueous-phase protocol that allows conversion of various olefins, including sterically hindered and demanding tetra-, tri-, and 1,1-disubstituted systems, as well as terminal alkenes, into the corresponding carboxylic acids in excellent yields. The outstanding stability of the catalyst system (26 recycling runs in 32 days without measurable loss of activity), is showcased in the preparation of an industrially relevant fatty acid. Key-to-success is the use of a built-in-base ligand under acidic aqueous conditions. This catalytic system is expected to provide a basis for new cost-competitive processes for the industrial production of carboxylic acids.
- Sang, Rui,Kucmierczyk, Peter,Dühren, Ricarda,Razzaq, Rauf,Dong, Kaiwu,Liu, Jie,Franke, Robert,Jackstell, Ralf,Beller, Matthias
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supporting information
p. 14365 - 14373
(2019/09/06)
-
- 3-Amino-1-methyl-1 H-pyridin-2-one-Directed PdII Catalysis: C(sp3)-H Activated Diverse Arylation Reaction
-
A new bidentate directing group, 3-amino-1-methyl-1H-pyridin-2-one, is introduced to achieve a powerful PdII metallacycle for selective γ-C(sp3)-H activation and arylation of aromatic and aliphatic carboxylic acid derivatives. The versatility of the directing group is validated for remote arylation of β-C(sp3)-H, β-C(sp2)-H, and γ-C(sp2)-H to achieve therapeutically important 2-pyridone analogues and arylated acid synthons. The traceless removal of the directing group to retrieve the directing element and carboxylic acids makes this method more interesting.
- Pati, Tanmay K.,Debnath, Sudipto,Kundu, Mrinalkanti,Khamrai, Uttam,Maiti, Dilip K.
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supporting information
p. 4062 - 4066
(2018/07/15)
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- Cationic Pd(II)/bipyridine-catalyzed conjugate addition of arylboronic acids to α,β-unsaturated carboxylic acids in aqueous media
-
An in-situ generated cationic Pd(II)/bipyridine-catalyzed conjugate addition of arylboronic acids to α,β-unsaturated carboxylic acids in water was developed and optimized. For most substrates, nearly quantitative yields were given, and the products can be purified by simple washing without column chromatography. The reaction can be scaled up to 1.0 g easily with excellent yields. Also the loading of catalyst can be lowered to 1.0 mol% with modest yields, and the reaction provided a mild and easy way to synthesize β-disubstituted carboxylic acids.
- Ni, Yuxin,Song, Kaixuan,Shen, Kai,Yang, Zhenyu,Liu, Rui,Lin, Shaohui,Pan, Qinmin
-
supporting information
p. 1192 - 1195
(2018/03/01)
-
- Direct β-Selective Hydrocarboxylation of Styrenes with CO2 Enabled by Continuous Flow Photoredox Catalysis
-
The direct β-selective hydrocarboxylation of styrenes under atmospheric pressure of CO2 has been developed using photoredox catalysis in continuous flow. The scope of this methodology was demonstrated with a range of functionalized terminal styrenes, as well as α-substituted and β-substituted styrenes.
- Seo, Hyowon,Liu, Aofei,Jamison, Timothy F.
-
supporting information
p. 13969 - 13972
(2017/10/17)
-
- Copper-catalyzed carboxylation of hydroborated disubstituted alkenes and terminal alkynes with cesium fluoride
-
A protocol for the hydrocarboxylation of disubstituted alkenes and terminal alkynes providing access to different secondary carboxylic acids and malonic acid derivatives has been developed. This methodology relies on an initial hydroboration using 9-BBN followed by carboxylation with carbon dioxide in the presence of a copper catalyst and the additive, cesium fluoride. Different cyclohexene, styrene, and stilbene derivatives could be utilized, and alkynes could be transformed into their corresponding dicarboxylic acids in good yields. Finally, six different terpenoids were carboxylated using the developed procedure. (Chemical Equation Presented).
- Juhl, Martin,Laursen, Simon L. R.,Huang, Yuxing,Nielsen, Dennis U.,Daasbjerg, Kim,Skrydstrup, Troels
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p. 1392 - 1396
(2017/05/24)
-
- Pd(II)/Bipyridine-Catalyzed Conjugate Addition of Arylboronic Acids to α,β-Unsaturated Carboxylic Acids. Synthesis of β-Quaternary Carbons Substituted Carboxylic Acids
-
Pd(II)/bipyridine-catalyzed conjugate addition of arylboronic acids to α,β-unsaturated carboxylic acids (including β,β-disubstituted acrylic acids) was developed and optimized, which provided a mild and convenient method for the highly challenging synthesis of β-quaternary carbons substituted carboxylic acids.
- Liu, Rui,Yang, Zhenyu,Ni, Yuxin,Song, Kaixuan,Shen, Kai,Lin, Shaohui,Pan, Qinmin
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p. 8023 - 8030
(2017/08/14)
-
- A Weinreb Amide Based Building Block for Convenient Access to β,β-Diarylacroleins: Synthesis of 3-Arylindanones
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Towards the synthesis of symmetrical and unsymmetrical β,β-diarylacroleins for assembling diarylmethine fragments present in biologically important molecules, we have developed a new Weinreb amide (WA) based building block, derived from propiolic acid. The WA functionality present in this compound allowed the sequential addition of various arylmagnesium bromide reagents in a controlled manner. The developed methodology for the access to β,β-diarylacroleins has been utilised for the synthesis of biologically important 3-arylindanone molecules. Synthesis of both symmetrical and unsymmetrical β,β-diarylacrolein and diarylmethine fragments, have been achieved via easily accessible and hitherto unknown Weinreb Amide (WA) based building block 11. The WA functionality allowed the sequential addition of nucleophiles such as arylmagnesium bromide in a controlled manner, which has enabled the synthesis of an important 3-arylindanone molecule.
- Tiwari, Praveen Kumar,Aidhen, Indrapal Singh
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p. 2637 - 2646
(2016/06/08)
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- New orally active diphenylmethyl-based ester analogues of dihydroartemisinin: Synthesis and antimalarial assessment against multidrug-resistant Plasmodium yoelii nigeriensis in mice
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A new series of ester analogues of artemisinin 8a–f, incorporating diphenylmethyl as pharmacologically privileged substructure, and 8g–j have been prepared and evaluated for their antimalarial activity against multidrug-resistant (MDR) Plasmodium yoelii nigeriensis in Swiss mice via oral route. These diphenylmethyl-based ester analogues 8a–f were found to be 2–4 folds more active than the antimalarial drugs β-arteether 4 and artesunic acid 5. Ester 8a, the most active compound of the series, provided complete protection to the infected mice at 24?mg/kg?×?4?days as well as 12?mg/kg?×?4?days, respectively. In this model β-arteether provided 100% and 20% protection at 48?mg/kg?×?4?days and 24?mg/kg?×?4?days, respectively.
- Chaudhary, Sandeep,Naikade, Niraj K.,Tiwari, Mohit K.,Yadav, Lalit,Shyamlal, Bharti Rajesh K.,Puri, Sunil K.
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p. 1536 - 1541
(2016/07/27)
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- Lewis acid-mediated β-selective hydrocarboxylation of α,α-diaryl- and α-arylalkenes with R3SiH and CO2
-
α,α-Diarylalkenes are successfully hydrocarboxylated with Et3SiH and CO2 with the aid of Et3SiB(C6F5)4 or EtAlCl2/Ph3SiCl to give carboxylic acids with a carboxy group at the β-position to the aryl groups. The EtAlCl2/Ph3SiCl-mediated reaction is also applicable to various α-arylalkenes. 1H NMR analysis of a mixture of EtAlCl2, Ph3SiCl, and Et3SiH strongly suggests the formation of a μ-H complex, [Ph3Si-H-SiEt3]+ AlEtCl3-, which is an equivalent of R3Si+ ions, while Et3SiB(C6F5)4 is an ion pair with a Et3Si+ ion. Therefore, in these reaction systems, a siloxycarbonylium, R3SiOCO+, is considered to be a common electrophile, the addition of which to the substrate, followed by trapping of the resulting cationic species with Et3SiH seems to afford the desired acid after aqueous workup.
- Tanaka, Shinya,Tanaka, Yuuki,Chiba, Masafumi,Hattori, Tetsutaro
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p. 3830 - 3834
(2015/06/08)
-
- Metabolism-guided discovery of a potent and orally bioavailable urea-based calcimimetic for the treatment of secondary hyperparathyroidism
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A series of urea based calcimimetics was optimized for potency and oral bioavailability. Crucial to this process was overcoming the poor pharmacokinetic properties of lead thiazole 1. Metabolism-guided modifications, characterized by the use of metabolite identification (ID) and measurement of time dependent inhibition (TDI) of CYP3A4, were essential to finding a compound suitable for oral dosing. Calcimimetic 18 exhibited excellent in vivo potency in a 5/6 nephrectomized rat model and cross-species pharmacokinetics.
- Wehn, Paul M.,Harrington, Paul E.,Carlson, Timothy J.,Davis, James,Deprez, Pierre,Fotsch, Christopher H.,Grillo, Mark P.,Lu, Jenny Ying-Lin,Morony, Sean,Pattabiraman, Kanaka,Poon, Steve F.,Reagan, Jeff D.,St. Jean Jr., David J.,Temal, Taoues,Wang, Minghan,Yang, Yuhua,Henley III, Charles,Lively, Sarah E.
-
p. 6625 - 6628
(2014/01/06)
-
- An efficient greener copper triflate-catalyzed C-3 benzylation of 4-hydroxycoumarin and some active methylene compounds
-
4-Hydroxycoumarin has been directly benzylated at C-3 position with a good number of secondary benzylic alcohols using copper triflate catalyst (2 mol%) in toluene under reflux. The protocol provides an efficient, expedient and atom-economic access to warfarin and coumatetralyl analogues with potential anticoagulant activity. The protocol has been extended to benzylation of 4-hydroxy-1-methylquinolin-2(1H)-1-one, N-methylbarbiturate and some other active methylene compounds with remarkable success.
- Ganguly, Nemai C.,Chandra, Sumanta
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p. 547 - 555
(2012/10/29)
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- Copper-catalyzed carboxylation of alkylboranes with carbon dioxide: Formal reductive carboxylation of terminal alkenes
-
Carboxylation of alkylboron compounds (alkyl-9-BBN) with CO2 proceeded in the presence of catalytic amounts of CuOAc/1,10-phenanthroline and a stoichiometric amount of KOtBu. The alkylboranes are easily and widely available through the alkene hydroboration, and thus the overall process represents a reductive carboxylation of alkenes with CO2. The broad functional group compatibility and the inexpensiveness of the Cu/1,10-phenathoroline catalyst system are attractive features of this protocol.(Figure Presented)
- Ohmiya, Hirohisa,Tanabe, Masahito,Sawamura, Masaya
-
supporting information; experimental part
p. 1086 - 1088
(2011/04/23)
-
- BTISA-catalyzed Friedel-Crafts bimolecular cyclization of cinnamic acid under superelectrophilic solvation conditions
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Friedel-Crafts bimolecular cyclizations of cinnamic acid and cinnamoyl chloride with aromatic compounds in strong and superstrong acids in present of 1 mol% BTISA were investigated. It was demonstrated that catalytic amounts of this new superacid have essential effect on such type of reactions. Its use makes possible the preparation of indanones with quantitative yields.
- Posternak, Anna G.,Garlyauskayte, Romute Yu.,Yagupolskii, Lev M.
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experimental part
p. 274 - 277
(2010/04/30)
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- Zeolite-directed cascade reactions: Cycliacyarylation versus decarboxyarylation of α,β-unsaturated carboxylic acids
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The interaction of α,β-unsaturated carboxylic acids with benzene derivatives was investigated in H-zeolites and led to two distinct but competing processes, cycliacyarylation and decarboxyarylation. Interestingly, H-USY selectively induced the cycliacyarylation cascade reaction, whereas H-ZSM5 selectively promoted the decarboxyarylation cascade.
- Chassaing, Stefan,Kumarraja, Mayilvasagam,Pale, Patrick,Sommer, Jean
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p. 3889 - 3892
(2008/02/11)
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- Conjugate addition of RMgX-3MeLi to α,β-unsaturated amides and α,β-unsaturated carboxylic acids
-
In the presence of 3 equivalents of MeLi, various Grignard reagents reacted with secondary α,β-unsaturated amides and α,β-unsaturated carboxylic acids to give the corresponding Michael adducts in good yields. Copyright
- Kikuchi, Mikiko,Niikura, Satomi,Chiba, Nao,Terauchi, Nahoko,Asaoka, Mono
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p. 736 - 737
(2008/02/09)
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- Superacid-Catalyzed Reactions of Cinnamic Acids and the Role of Superelectrophiles
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The chemistry of cinnamic acids and related compounds has been studied. In superacid-catalyzed reactions with arenes, two competing reaction mechanisms are proposed. Both mechanisms involve the formation of dicationic intermediates (superelectrophiles), and the reactions can lead to either chalcone-type products or indanone products. The direct observation of a dicationic species (by low-temperature 13C NMR) is reported. We provide clear evidence that protonated carboxylic acid groups (or the corresponding acyl cation) can enhance the reactivity of an adjacent electrophilic center. Triflic acid is also found to be an effective acid catalyst for the direct synthesis of some electron-deficient chalcones and heterocyclic chalcones from cinnnamic acids.
- Rendy, Rendy,Zhang, Yun,McElrea, Aaron,Gomez, Alma,Klumpp, Douglas A.
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p. 2340 - 2347
(2007/10/03)
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- Reactions of active methylene compounds with benzhydrol during solvolysis in formic acid
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Formic acid reacts with benzhydrol to give benzhydryl formate, which reacts with active methylene compounds in refluxing formic acid to give either C-alkylation or Ritter reaction products. The product formed is determined by the equilibrium enol content of the active methylene compound. These reaction conditions avoid the use of halogenated reaction solvents, and the pure products are isolated without recourse to chromatography.
- Gullickson, Glen C.,Lewis, David E.
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p. 385 - 388
(2007/10/03)
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- Polyethylene glycol mediated reductive decyanation of diphenylacetonitrile moderately enhanced by microwave heating
-
An efficient and clean procedure for the preparation of alkyldiphenylmethanes and 4,4-diphenylbutylamines from their corresponding nitriles by using sodium hydroxide-polyethylene glycol reagent system in a domestic microwave oven is described. The products are isolated by simple aqueous work up in excellent yields.
- Bendale,Chowdhury,Khadilkar
-
p. 433 - 435
(2007/10/03)
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- Addition of organolithium reagents to cinnamic acids
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Reaction of tert-butyllithium with p- and m-substituted cinnamic acids at low temperature affords mixtures of 1,4- and 1,3-addition products, whose composition depend on the nature of the substituents. Electron-donating and electron-withdrawing groups favour 1,4- and 1,3-additions, respectively. Linear correlations are obtained with electronic effect and with radical substituent constants.
- Aurell, Maria Jose,Banuls, Maria Jose,Mestres, Ramon,Munoz, Elena
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p. 831 - 846
(2007/10/03)
-
- Reactions d'addition conjuguee d'organolithiens aux acides carboxyliques α, β-insatures
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In THF at -78 deg C, organolithium derivatives and unprotected α,β-unsaturated carboxylic acids give a conjugated addition reaction. Reactions of 1- and 2-napthoic acids with various organolithium derivatives and electrophiles are reported. Two X-ray studies show that the reaction occurs with a good diastereoselectivity: the dilithiated enolate formed as an intermediate adds the electrophile exclusively via the face opposite to that of the organolithium. A study of the 1H NMR spectra of the products obtained shows that these compounds adopt a preffered conformation in solution. The protonolysis of the intermediate enolate by trifluoroacetic acid in an inverted mode gives rise to the formation of 1,2-disubstituted dihydronapthalenes. With acyclic α,β-unsaturated carboxylic acids, the diastereoselectivity of the reaction is marginal. With secondary butyllithium, the protonolysis of the intermediate enolates gives a 1,4-addition and an average diastereoselectivity. Reaction of phenylpropiolic acid with butyllithium gives rise to the formation of a produst resulting from a trans addition to the triple bond; the organolithium derivative adds in α to the carboxylic group. - Key words: 1,4-addition reactions; carboxylic acids; organolithium derivatives.
- Mortier, Jacques,Vaultier, Michel,Plunian, Barbara,Sinbandhit, Sourisak
-
-
- Stereocontrol in the intramolecular Buchner reaction of diazoketones
-
Rhodium(II) acetate catalysed intramolecular Buchner cyclisation of a series of diazoketones 1 proceeds with excellent diastereoselectivity to produce the trans substituted azulenones 2, which exist as a rapidly equilibrating cycloheptatriene-norcaradiene system, from which the norcaradiene tautomers can be efficiently trapped as PTAD cycloadducts 4. The cyclisation-cycloaddition sequence can be conducted in either a stepwise or a tandem process, leading to the pentacyclic systems 4 as a single diastereomer in each case. In the reaction of diazoketone If intramolecular cyclopropanation competes with cyclisation to the aromatic ring.
- Maguire, Anita R.,Buckley, N. Rachael,O'Leary, Patrick,Ferguson, George
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p. 4077 - 4091
(2007/10/03)
-
- Preparation of pharmaceuticals by hydroformylation. Part III. The synthesis of N-(4-Pyridyl)-3,3-diphenyl-1-aminopropane (Phenpyramine, Milverine)
-
N-(4-Pyridyl)-3,3-diphenyl-1-aminopropane (1) (Phenpyramine, Milverine), an important amino-pyridine derivative endowed with Muscarinic antagonist activity, is prepared starting from 1,1-diphenylethene using the hydroformylation as key the step in the reaction scheme: the obtained aldehyde was transformed in the desired compound 1 by a three steps reaction sequence; the overall yield was up to 42.8%.
- Marchetti,Sechi,Botteghi,Paganelli
-
-
- Directed conjugate addition of organolithium reagents to α,β-unsaturated carboxylic acids
-
α,β-Unsaturated carboxylic acids undergo predominantly conjugate addition with organolithium reagents at low temperature (-78 °C) in THF and lead to various substituted alkanoic acids after quenching with electrophiles; with (E)-3-phenylpropenoic acid, this tandem alkylation sequence also affords significant amounts of isomeric 1,3-addition products.
- Plunian, Barbara,Vaultier, Michel,Mortier, Jacques
-
-
- N-acyl sulfamic acid esters (or thioesters), N-acyl sulfonamides, and N-sulfonyl carbamic acid esters (or thioesters) as hypercholesterolemic agents
-
The present invention is directed to compounds useful for the regulation of cholesterol of Formula I, methods for using them and pharmaceutical compositions thereof, STR1 wherein X and Y are oxygen, sulfur, or (CR'R")n wherein n is 1 to 4; R is hydrogen, alkyl, or benzyl; R1 and R2 are phenyl, substituted phenyl, naphthyl, substituted naphthyl, an aralkyl group, an alkyl chain, adamantyl, or a cycloalkyl group.
- -
-
-
- A Very Useful and Mild Method for the Protection and Deprotection of Carboxylic Acids
-
3-Methylbut-2-enoate carboxylic acid can be a good protecting group of carboxylic acids and can be removed easily by using iodine in cyclohexane at room temperature.Key words: Protection, deprotection, 3-methylbut-2-enoate carboxylic acid, iodine.
- Cossy, Janine,Albouy, Arnaud,Scheloske, Michael,Pardo, Domingo Gomez
-
p. 1539 - 1540
(2007/10/02)
-
- Convenient Synthetic Sequence for the Preparation of Indanones
-
A convenient and general methods is reported for the synthesis of indanones from aryl ketones or aldehydes.
- Smonou, Ioulia,Orfanopoulos, Michael
-
p. 1387 - 1397
(2007/10/02)
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- KINETICS AND MECHANISM OF THE ADDITION OF ALCOHOLS TO KETENES IN DIETHYL ETHER SOLUTION IN THE PRESENCE OF BORON TRIFLUORIDE
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The kinetics are reported of the boron trifluoride-catalysed additions of seven alcohols to dimethylketene in diethyl ether solution at 25 deg C.All the reactions involve the rapid initial formation of 1:1 alcohol-boron trifluoride adduct (formation constant K) which transfer a proton to the ketene in the slow step of the addition.For t-butyl alcohol, ethanol, methanol, phenylmethanol, and 2-chloroethanol the K values are > 1000, 320+/-50, 300+/-50, 80+/-20, and 65+/-15 l/mol, respectively.The more acididc an alcohol the faster is the reaction of its 1:1 boron trifluoride adduct with the ketene.For t-butyl alcohol the relatively slow reaction of its adduct is catalysed by a further molecule of the adduct and by free boron trifluoride.At 25 deg C the spontaneous addition of ethanol to diphenylketene in ether (like that to dimethylketene) is first order in the ketene and third order in the ethanol concentration.In this reaction diphenylketene is ca. 10-fold more reactive than the dimethyl derivative in the concentration range studied.Whereas the addition of boron trifluoride to the solution catalyses the addition of ethanol (and the other alcohols) to dimethylketene to such an extent that the spontaneous addition makes a negligible contribution to the overall rate, with diphenylketene the alcohol-boron trifluoride adduct is relatively so unreactive that added boron trifluoride strongly inhibits the spontaneous addition.The ethanol-boron trifluoride adducts is > 10E4-fold less reactive towards diphenylketene.These results support our previous conclusions concerning additions of acidic species to ketenes.
- Poon, Nai L.,Satchell, Derek P. N.
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p. 1083 - 1088
(2007/10/02)
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- Synthese de methoxycarbonylindenes, dihydro-1,2 naphtalenes et benzocycloheptene. Obtention des indanones-1, des tetralones-1 et de la benzosuberone correspondantes
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The synthesis of methoxycarbonylindenes, 1,2-dihydro-naphtalenes, and benzocycloheptene starting from the corresponding 1-indanones, 1-tetralones, and benzosuberone is reported.The starting ketones were synthesized by methods described in the literature which were optimized; in some cases new processes are described.
- Verbel, Joel,Carrie, Robert
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p. 116 - 124
(2007/10/02)
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- THE REACTION OF DIAZOACETIC ESTER WITH THIOBENZOPHENONE
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Methyl diazoacetate reacts with two equivalents of thiobenzophenone to furnish two isomeric 1,3-dithiolanes and nitrogen; the intermediate thiocarbonyl ylide is intercepted by 1,3-dipolar cycloaddition or undergoes electrocyclic ring closure.
- Kalwinsch, Ivars,Huisgen, Rolf
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p. 3941 - 3944
(2007/10/02)
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- Reactions involving carbon tetrahalides and α-methyl ketones or ketones having α,α'-hydrogens
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A process for preparing aldehydes, ketones, carboxylic acids and esters by reaction of various substrates with carbon tetrahalides in the presence of a strong base. The reactions are accelerated by the presence of a polar solvent. Anions of the substrate attack the carbon tetrahalide to produce a halogenated intermediate and a dihalocarbene. The halogenated intermediate reacts with the base to form the indicated products. By the reactions of this process, primary alcohols are converted to aldehydes, carboxylic acids and esters, secondary alcohols are converted to ketones and ketones having an α-methyl group or both α and α' hydrogens are converted to carboxylic acids and esters. Non α-methyl ketones having α but no α' hydrogens are simply α-halogenated. The dihalocarbene generated in the reaction may attack the product, solvent, or another substrate to form other products.
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