cas 612-15-7, 2-METHOXYSTYRENE | Articles data

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Functionalized styrene synthesis via palladium-catalyzed C[sbnd]C cleavage of aryl ketones
We report herein the synthesis of functionalized styrenes via palladium-catalyzed Suzuki–Miyaura cross-coupling reaction between aryl ketone derivatives and potassium vinyltrifluoroborate. The employment of pyridine-oxazoline ligand was the key to the cleavage of unstrained C[sbnd]C bond. A variety of functional groups and biologically important moleculars were well tolerated. The orthogonal Suzuki–Miyaura coupling demonstrated the synthetic practicability.
Zhang, Xu,Wang, Zhen-Yu,Wang, Xing,Xu, Hui,Dai, Hui-Xiong
(2022/03/31)

Nickel-Catalyzed Reductive Cross-Coupling of Aryl Bromides with Vinyl Acetate in Dimethyl Isosorbide as a Sustainable Solvent
A nickel-catalyzed reductive cross-coupling has been achieved using (hetero)aryl bromides and vinyl acetate as the coupling partners. This mild, applicable method provides a reliable access to a variety of vinyl arenes, heteroarenes, and benzoheterocycles, which should expand the chemical space of precursors to fine chemicals and polymers. Importantly, a sustainable solvent, dimethyl isosorbide, is used, making this protocol more attractive from the point of view of green chemistry.
Su, Mincong,Huang, Xia,Lei, Chuanhu,Jin, Jian
supporting information
p. 354 - 358
(2022/01/15)

Application of tungsten oxide supported monatomic catalyst in preparation of aromatic compound by hydrogenolysis of lignin
The invention provides application of a tungsten oxide supported monatomic catalyst in preparation of aromatic compounds by hydrogenolysis of lignin. According to the method, various beta-O-4 model molecules, organic lignin, lignosulfonate and alkali lignin are taken as raw materials, and high-selectivity cracking of aryl ether bonds is realized in a hydrogen atmosphere at the temperature of 150-240 DEG C and the pressure of 0.7-3.0 MPa to obtain the aromatic compound. Compared with the prior art, the method has the advantages that when renewable natural biomass is used as the raw material and different lignin is used as the raw material for conversion, the highest yield of the aromatic bio-oil is 72%. Raw materials are cheap and wide in source; inorganic acid and alkali are not needed, and generation of a large amount of alkali liquor in traditional lignin catalysis is avoided; the method has the characteristics of cheap tungsten-based catalyst, green reaction process, atom economy and the like, and also has the characteristics of mild reaction conditions, high activity and selectivity, environment-friendly reaction process and the like.
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Paragraph 0044-0051

(2021/05/22)

Photocatalytic carbocarboxylation of styrenes with CO2for the synthesis of γ-aminobutyric esters
Metal-free photoredox-catalyzed carbocarboxylation of various styrenes with carbon dioxide (CO2) and amines to obtain γ-aminobutyric ester derivatives has been developed (up to 91% yield, 36 examples). The radical anion of (2,3,4,6)-3-benzyl-2,4,5,6-tetra(9H-carbazol-9-yl)benzonitrile (4CzBnBN) possessing a high reduction potential (?1.72 Vvs.saturated calomel electrode (SCE)) easily reduces both electron-donating and electron-withdrawing group-substituted styrenes.
Hahm, Hyungwoo,Han, Min Su,Hong, Sukwon,Kim, Jiyun,Ryoo, Jeong Yup
p. 6301 - 6312
(2021/07/28)

Iron-Catalyzed Direct Julia-Type Olefination of Alcohols
Herein, we report an iron-catalyzed, convenient, and expedient strategy for the synthesis of styrene and naphthalene derivatives with the liberation of dihydrogen. The use of a catalyst derived from an earth-abundant metal provides a sustainable strategy to olefins. This method exhibits wide substrate scope (primary and secondary alcohols) functional group tolerance (amino, nitro, halo, alkoxy, thiomethoxy, and S- A nd N-heterocyclic compounds) that can be scaled up. The unprecedented synthesis of 1-methyl naphthalenes proceeds via tandem methenylation/double dehydrogenation. Mechanistic study shows that the cleavage of the C-H bond of alcohol is the rate-determining step.
Landge, Vinod G.,Babu, Reshma,Yadav, Vinita,Subaramanian, Murugan,Gupta, Virendrakumar,Balaraman, Ekambaram
p. 9876 - 9886
(2020/09/03)

Palladium-Catalyzed Mizoroki-Heck Reaction of Nitroarenes and Styrene Derivatives
We have developed a Mizoroki-Heck reaction of nitroarenes with alkenes under palladium catalysis. The use of a Pd/BrettPhos catalyst promoted the alkenylation, whereas other catalysts led to a decrease in the product yield. In addition to nitroarenes, nitroheteroarenes were also applicable to the present reaction. The combination of a nucleophilic aromatic substitution (SNAr) with the denitrative alkenylation produced a multifunctionalized arene in a one-pot operation.
Okita, Toshimasa,Asahara, Kitty K.,Muto, Kei,Yamaguchi, Junichiro
supporting information
p. 3205 - 3208
(2020/04/10)

Ruthenium catalyzed synthesis method of primary amine
The invention belongs to the field of organic synthesis, and discloses a ruthenium catalyzed synthesis method of primary amine. A ruthenium complex is taken as a catalyst; and a compound (A) and a compound (B) carry out reactions to obtain a compound (C); wherein R1 represents hydrogen or an alkyl group; R2 represents hydrogen or an alkyl group; R3 represent hydrogen, an alkyl group, or a phenyl group; R4 represent one of following structures shown in the description; n represents 0, 1, 2, or 3; R5 represents an alkyl group, an alkoxyl group, an ester group, a phenyl group, or a halogen atom,when n>=2, at least two R5(s) can be identical or different, m represents 0, 1, 2, or 3, R6 represents an alkyl group, an alkoxyl group, an ester group, or a halogen atom, and when m>=2, at least twoR6(s) can be identical or different. The method has the advantages of simple operation, mild conditions, small using amount of catalysts, wide substrate application range, no need of inert gas, and high yield.
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Paragraph 0049-0052

(2020/03/09)

Pd-Catalyzed Synthesis of Vinyl Arenes from Aryl Halides and Acrylic Acid
Acrylic acid is presented as an inexpensive, non-volatile vinylating agent in a palladium-catalyzed decarboxylative vinylation of aryl halides. The reaction proceeds through a Heck reaction of acrylic acid, immediately followed by protodecarboxylation of the cinnamic acid intermediate. The use of the carboxylate group as a deciduous directing group ensures high selectivity for monoarylated products. The vinylation process is generally applicable to diversely substituted substrates. Its utility is shown by the synthesis of drug-like molecules and the gram-scale preparation of key intermediates in drug synthesis.
Gao, Yang,Ou, Yang,Goo?en, Lukas J.
supporting information
p. 8709 - 8712
(2019/06/17)

Nickel(ii)-catalyzed direct olefination of benzyl alcohols with sulfones with the liberation of H2
A nickel(ii)-catalyzed direct olefination of benzyl alcohols with sulfones to access various terminal and internal olefins with the liberation of hydrogen gas is reported.
Landge, Vinod G.,Yadav, Vinita,Subaramanian, Murugan,Dangarh, Pragya,Balaraman, Ekambaram
supporting information
p. 6130 - 6133
(2019/06/03)

Mechanism of the Bis(imino)pyridine-Iron-Catalyzed Hydromagnesiation of Styrene Derivatives
Iron-catalyzed hydromagnesiation of styrene derivatives offers a rapid and efficient method to generate benzylic Grignard reagents, which can be applied in a range of transformations to provide products of formal hydrofunctionalization. While iron-catalyzed methodologies exist for the hydromagnesiation of terminal alkenes, internal alkynes, and styrene derivatives, the underlying mechanisms of catalysis remain largely undefined. To address this issue and determine the divergent reactivity from established cross-coupling and hydrofunctionalization reactions, a detailed study of the bis(imino)pyridine iron-catalyzed hydromagnesiation of styrene derivatives is reported. Using a combination of kinetic analysis, deuterium labeling, and reactivity studies as well as in situ 57Fe M?ssbauer spectroscopy, key mechanistic features and species were established. A formally iron(0) ate complex [iPrBIPFe(Et)(CH2a?CH2)]- was identified as the principle resting state of the catalyst. Dissociation of ethene forms the catalytically active species which can reversibly coordinate the styrene derivative and mediate a direct and reversible β-hydride transfer, negating the necessity of a discrete iron hydride intermediate. Finally, displacement of the tridentate bis(imino)pyridine ligand over the course of the reaction results in the formation of a tris-styrene-coordinated iron(0) complex, which is also a competent catalyst for hydromagnesiation.
Neate, Peter G. N.,Greenhalgh, Mark D.,Brennessel, William W.,Thomas, Stephen P.,Neidig, Michael L.
supporting information
p. 10099 - 10108
(2019/07/04)

Additive-modulated switchable reaction pathway in the addition of alkynes with organosilanes catalyzed by supported Pd nanoparticles: Hydrosilylation: versus semihydrogenation
We herein report supported Pd nanoparticles on N,O-doped hierarchical porous carbon as a single operation catalyst-enabled additive-modulated reaction pathway for alkynes addition with organosilanes between hydrosilyation and semihydrogenation. In the case of alkynes hydrosilylation, a simple iodide ion as an additive has a promotion effect on the activity and regio- and stereoselectivity, where iodide can coordinate with Pd NPs via strong δ donation to increase the electron density of the Pd atom, resulting in an increased ability for the oxidative addition of hydrosilane as the rate-determining step to make the reaction proceed efficiently to afford vinylsilanes in high yields with excellent regio- and stereoselectivity. For the catalytic transfer semihydrogenation of alkynes, water was introduced to mix with organosilane to form a silanol together with the generation of hydrogen atoms on the Pd NPs surface or the liberation of H2 gas as a reducing agent, whereby the quantitative reduction of alkynes was achieved with exclusive selectivity to alkenes. In both cases, the catalyst could be recycled several times without a significant loss in activity or selectivity. A broad range of alkyl and aryl alkynes with various functional groups are compatible with the reaction conditions. The role the additive exerted in each reaction was extensively investigated through control experiments as well as the kinetic isotopic effect along with spectroscopic characterization. In addition, the respective mechanism operating in both reactions was proposed.
Duan, Yanan,Ji, Guijie,Zhang, Shaochun,Chen, Xiufang,Yang, Yong
p. 1039 - 1050
(2018/03/05)

A [...] reagent catalytic synthesis method and its application (by machine translation)
The invention provides a method for catalytic synthesis of [...] reagent method and its application, the [...] reagent of formula (1) as shown in the structure of the organic solution: Its catalytic synthesis method is: under protection of inert gas, (II) shown [...] catalyst copper complex and active zinc powder added to the organic solvent, under a certain temperature [...] methyl bromide, then temperature reaction until the zinc powder the reaction is complete, the obtained white suspension is [...] reagent. (II), the invention compared with the prior art, the major advantage of: provides a [...] reagent catalytic synthesis method, is formed from a copper compound as a catalyst in the synthesis of the reagent [...] effect, and in the carbonyl of methylene compounds have been obtained in the application. (by machine translation)
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Paragraph 0039; 0040; 0044; 0045

(2018/04/28)

Terminal Alkenes from Acrylic Acid Derivatives via Non-Oxidative Enzymatic Decarboxylation by Ferulic Acid Decarboxylases
Fungal ferulic acid decarboxylases (FDCs) belong to the UbiD-family of enzymes and catalyse the reversible (de)carboxylation of cinnamic acid derivatives through the use of a prenylated flavin cofactor. The latter is synthesised by the flavin prenyltransferase UbiX. Herein, we demonstrate the applicability of FDC/UbiX expressing cells for both isolated enzyme and whole-cell biocatalysis. FDCs exhibit high activity with total turnover numbers (TTN) of up to 55000 and turnover frequency (TOF) of up to 370 min?1. Co-solvent compatibility studies revealed FDC's tolerance to some organic solvents up 20 % v/v. Using the in-vitro (de)carboxylase activity of holo-FDC as well as whole-cell biocatalysts, we performed a substrate profiling study of three FDCs, providing insights into structural determinants of activity. FDCs display broad substrate tolerance towards a wide range of acrylic acid derivatives bearing (hetero)cyclic or olefinic substituents at C3 affording conversions of up to >99 %. The synthetic utility of FDCs was demonstrated by a preparative-scale decarboxylation.
Aleku, Godwin A.,Prause, Christoph,Bradshaw-Allen, Ruth T.,Plasch, Katharina,Glueck, Silvia M.,Bailey, Samuel S.,Payne, Karl A. P.,Parker, David A.,Faber, Kurt,Leys, David
p. 3736 - 3745
(2018/08/03)

Interrogating Pd(II) Anion Metathesis Using a Bifunctional Chemical Probe: A Transmetalation Switch
Ligand metathesis of Pd(II) complexes is mechanistically essential for cross-coupling. We present a study of halide→OH anion metathesis of (Ar)PdII complexes using vinylBPin as a bifunctional chemical probe with Pd(II)-dependent cross-coupling pathways. We identify the variables that profoundly impact this event and allow control to be leveraged. This then allows control of cross-coupling pathways via promotion or inhibition of organoboron transmetalation, leading to either Suzuki-Miyaura or Mizoroki-Heck products. We show how this transmetalation switch can be used to synthetic gain in a cascade cross-coupling/Diels-Alder reaction, delivering borylated or non-borylated carbocycles, including steroid-like scaffolds.
Molloy, John J.,Seath, Ciaran P.,West, Matthew J.,McLaughlin, Calum,Fazakerley, Neal J.,Kennedy, Alan R.,Nelson, David J.,Watson, Allan J. B.
supporting information
p. 126 - 130
(2018/01/17)

Palladium-Catalyzed Chemoselective Protodecarboxylation of Polyenoic Acids
Conditions for the first palladium-catalyzed chemoselective protodecarboxylation of polyenoic acids to give the desired polyenes in good yields are presented. The reactions proceed under mild conditions using either a Pd(0) or Pd(II) catalyst and tolerate a variety of aryl and aliphatic substitutions. Unique aspects of the reaction include the requirement of phosphines, water, and a polyene adjacent to the carboxylic acid.
Al-Huniti, Mohammed H.,Perez, Mark A.,Garr, Matthew K.,Croatt, Mitchell P.
supporting information
p. 7375 - 7379
(2019/01/03)

Model Guided Development of a Simple Catalytic Method for the Synthesis of Unsymmetrical Stilbenes by Sequential Heck Reactions of Aryl Bromides with Ethylene
Stilbenes are important and useful structural moieties, but methods for their preparation typically possess numerous inefficiencies. Presented here is a methodology for the two-step, one pot preparation of unsymmetrical stilbenes via sequential Heck reactions. The first Heck reaction with ethylene gas was analysed as a function of temperature and pressure for electronically differentiated naphthyl bromides and model-aided reaction optimization was utilized to define the system. In addition, reactNMR was utilized to determine ethylene solubility in common organic solvents useful for Heck reactions. Finally, an optimized sequential Heck reaction process was developed and applied to a range of substrates allowing for efficient preparation of unsymmetrical stilbenes, including the natural antioxidant, pterostilbene. (Figure presented.).
Barlow, Helen,Buser, Jonas Y.,Glauninger, Hendrik,Luciani, Carla V.,Martinelli, Joseph R.,Oram, Niall,Thompson-Van Hook, Nichole,Richardson, Jeffery
p. 2678 - 2690
(2018/06/04)

Rapid Access to Ortho-Alkylated Vinylarenes from Aromatic Acids by Dearomatization and Tandem Decarboxylative C-H Olefination/Rearomatization
A two-step straightforward method for the preparation of ortho-alkylated vinylarenes from readily available benzoic acids is described. The synthetic route involves the dearomatization of benzoic acids by Birch reduction providing alkylated cyclohexa-2,5-dienyl-1-carboxylic acids. The diene subsequently undergoes a decarboxylative C-H olefination followed by rearomatization to deliver ortho-alkylated vinylarene. Mechanistic studies suggest that a Pd/Ag bimetallic catalytic system is important in the tandem decarboxylative C-H olefination/rearomatization step.
Tsai, Hung-Chang,Huang, Yen-Hsiang,Chou, Chih-Ming
supporting information
p. 1328 - 1332
(2018/03/09)

Selective Semihydrogenation of Alkynes Catalyzed by Pd Nanoparticles Immobilized on Heteroatom-Doped Hierarchical Porous Carbon Derived from Bamboo Shoots
Highly dispersed palladium nanoparticles (Pd NPs) immobilized on heteroatom-doped hierarchical porous carbon supports (N,O-carbon) with large specific surface areas are synthesized by a wet chemical reduction method. The N,O-carbon derived from naturally abundant bamboo shoots is fabricated by a tandem hydrothermal–carbonization process without assistance of any templates, chemical activation reagents, or exogenous N or O sources in a simple and ecofriendly manner. The prepared Pd/N,O-carbon catalyst shows extremely high activity and excellent chemoselectivity for semihydrogenation of a broad range of alkynes to versatile and valuable alkenes under ambient conditions. The catalyst can be readily recovered for successive reuse with negligible loss in activity and selectivity, and is also applicable for practical gram-scale reactions.
Ji, Guijie,Duan, Yanan,Zhang, Shaochun,Fei, Benhua,Chen, Xiufang,Yang, Yong
p. 3427 - 3434
(2017/09/15)

Efficient synthesis of functionalized olefins by Wittig reaction using Amberlite resin as a mild base
A convenient procedure for the synthesis of olefins by the reaction of stabilized, semistabilized, and nonstabilized phosphorous ylides with various aldehydes or ketone using Amberlite resin as a mild base is described. Our developed method offers facile and racemization-free synthesis of α,β-unsaturated amino esters and chiral allylic amine. The developed methodology offers mild reaction conditions, high efficiency, and facile isolation of the final products, a practical alternative to known procedures.
Valkute, Tushar R.,Aratikatla, Eswar K.,Bhattacharya, Asish K.
p. 581 - 589
(2017/03/15)

Electrosynthesis of vinyl sulfones from alkenes and sulfonyl hydrazides mediated by KI: Аn electrochemical mechanistic study
A variety of vinyl sulfones were prepared from alkenes and sulfonyl hydrazides via electrochemical oxidative sulfonylation. The reaction proceeds in an experimentally convenient undivided electrochemical cell equipped with graphite and iron electrodes employing KI as a redox catalyst and a supporting electrolyte. Applying extremely high current density up to 270 mA/cm2 permits rapid synthesis in a compact reactor and with small surface area electrodes. A possible reaction mechanism was proposed with the use of cyclic voltammetry. It is the combination of anodic and cathodic processes in this reaction that makes it possible to obtain products under mild conditions with yields from moderate to high.
Terent'ev, Alexander O.,Mulina, Olga M.,Pirgach, Dmitry A.,Ilovaisky, Alexey I.,Syroeshkin, Mikhail A.,Kapustina, Nadezhda I.,Nikishin, Gennady I.
supporting information
p. 6871 - 6879
(2017/11/06)

Norepinephrine alkaloids as antiplasmodial agents: Synthesis of syncarpamide and insight into the structure-activity relationships of its analogues as antiplasmodial agents
Syncarpamide 1, a norepinephrine alkaloid isolated from the leaves of Zanthoxylum syncarpum (Rutaceae) exhibited promising antiplasmodial activities against Plasmodium falciparum with reported IC50 values of 2.04 μM (D6 clone), 3.06 μM (W2 clone) and observed by us 3.90 μM (3D7 clone) and 2.56 μM (K1 clone). In continuation of our work on naturally occurring antimalarial compounds, synthesis of syncarpamide 1 and its enantiomer, (R)-2 using Sharpless asymmetric dihydroxylation as a key step has been accomplished. In order to study structure-activity-relationship (SAR) in detail, a library of 55 compounds (3–57), which are analogues/homologues of syncarpamide 1 were synthesized by varying the substituents on the aromatic ring, by changing the stereocentre at the C-7 and/or by varying the acid groups in the ester and/or amide side chain based on the natural product lead molecule and further assayed in vitro against 3D7 and K1 strains of P. falciparum to evaluate their antiplasmodial activities. In order to study the effect of position of functional groups on antiplasmodial activity profile, a regioisomer (S)-58 of syncarpamide 1 was synthesized however, it turned out to be inactive against both the strains. Two compounds, (S)-41 and its enantiomer, (R)-42 having 3,4,5-trimethoxy cinnamoyl groups as side chains showed better antiplasmodial activity with IC50 values of 3.16, 2.28 μM (3D7) and 1.78, 2.07 μM (K1), respectively than the natural product, syncarpamide 1. Three compounds (S)-13, (S)-17, (S)-21 exhibited antiplasmodial activities with IC50 values of 6.39, 6.82, 6.41 μM against 3D7 strain, 4.27, 7.26, 2.71 μM against K1 strain and with CC50 values of 147.72, 153.0, >200 μM respectively. The in vitro antiplasmodial activity data of synthesized library suggests that the electron density and possibility of resonance in both the ester and amide side chains increases the antiplasmodial activity as compared to the parent natural product 1. The natural product syncarpamide 1 and four analogues/homologues out of the synthesized library of 55, (S)-41, (R)-42, (S)-55 and (S)-57 were assayed in vivo assay against chloroquine-resistant P. yoelii (N-67) strain of Plasmodium. However, none of the five molecules, 1, (S)-41, (R)-42, (S)-55 and (S)-57 exhibited any promising in vivo antimalarial activity against P. yoelii (N-67) strain. Compounds 4, 6, 7 and 11 showed high cytotoxicities with CC50 values of 5.87, 5.08, 6.44 and 14.04 μM, respectively. Compound 6 was found to be the most cytotoxic as compared to the standard drug, podophyllotoxin whereas compounds 4 and 7 showed comparable cytotoxicities to podophyllotoxin.
Aratikatla, Eswar K.,Valkute, Tushar R.,Puri, Sunil K.,Srivastava, Kumkum,Bhattacharya, Asish K.
supporting information
p. 1089 - 1105
(2017/08/03)

Fluorinative Rearrangements of Substituted Phenylallenes Mediated by (Difluoroiodo)toluene: Synthesis of α-(Difluoromethyl)styrenes
Phenylallenes undergo fluorinative rearrangement upon the action of (difluoroiodo)toluene in the presence of 20 mol % BF3?OEt2 to yield α-difluoromethyl styrenes. This unprecedented reaction was entirely chemoselective for the internal allene π bond, and showed remarkable regioselectivity during the fluorination event. Substituted phenylallenes, phenylallenes possessing both phenyl- and α-allenyl substituents, and diphenylallenes were investigated, and good functional-group compatibility was observed throughout. The ease with which allenes can be prepared on a large scale, and the operational simplicity of this reaction allowed us to rapidly access fluorine-containing building blocks that have not been accessed by conventional deoxyfluorination strategies.
Zhao, Zhensheng,Racicot, Léanne,Murphy, Graham K.
supporting information
p. 11620 - 11623
(2017/09/11)

Organoselenium-Catalyzed Regioselective C?H Pyridination of 1,3-Dienes and Alkenes
An efficient approach for organoselenium-catalyzed regioselective C?H pyridination of 1,3-dienes to form pyridinium salts has been developed. This method was also successfully applied to direct C?H pyridination of alkenes. Fluoropyridinium reagents, or initially loaded pyridine derivatives, acted as pyridine sources in the pyridination reactions. The obtained pyridinium salts could be further converted under different conditions. This work is the first example of catalytic C-2 direct C?H functionalization of 1,3-dienes and the first case of organoselenium-catalyzed C?H pyridination.
Liao, Lihao,Guo, Ruizhi,Zhao, Xiaodan
supporting information
p. 3201 - 3205
(2017/03/17)

SQUALENE COMPOUNDS AS MODULATORS OF LDL-RECEPTOR EXPRESSION
The present invention relates to compounds that modify low density lipoprotein receptor (LDLR) expression. The compounds have the structural formula I shown below: wherein m, R1, n, R2 and R3 are each as defined herein. The present invention also relates to processes for the preparation of these compounds, to pharmaceutical compositions comprising them, and to their use in the treatment of diseases or disorders associated with elevated levels of low density lipoprotein cholesterol (LDL-C).
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Paragraph 0005; 0011

(2016/04/20)

2 - (O-hydroxyphenyl) cyclopropane-1-preparation of formic acid method
A preparation method of 2-(o-hydroxyphenyl)cyclopropane-1-carboxylic acid is provided. With o-alkoxy cinnamic acid as a raw material, 2-(o-alkoxyphenyl)cyclopropane-1,1-ethyl dicarboxylate is obtained through pyrolysis decarboxylation, halogen addition and cyclopropanation, and then the novel tobacco spice 2-(o-hydroxyphenyl)cyclopropane-1-carboxylic acid is prepared through deestering, hydrolysis, demethylation and other steps. The raw material and reagents in the route are all commercial products, so that the raw material is easy to obtain; the reaction steps are all classic organic reactions, especially the cyclopropanation step avoids the use of expensive trimethylsulfoxonium halogen (TMSOX, wherein X is Cl, Br or I) reagents, and thus the cost of production is significantly reduced. Through process optimization, the overall yield of the reaction reaches 53%. The method has the advantages of simple operation, high synthesis yield, low costs of the raw material and the reagents, easy scale production and the like. The 2-(o-hydroxyphenyl)cyclopropane-1-carboxylic acid prepared by the method is mainly used in spice and essence industries.
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Paragraph 0030; 0031; 0033; 0034

(2017/03/14)

Switching the Cleavage Sites in Palladium on Carbon-Catalyzed Carbon-Carbon Bond Disconnection
We have demonstrated a palladium on carbon-catalyzed approach to regioselectively alter the cleavage sites of the C-C bonds of cinnamaldehyde derivatives by a slight change in the reaction conditions in isopropanol under an O2 atmosphere. Styrene derivatives could be selectively formed by the addition of Na2CO3 in association with the dissociation of carbon monoxide, while benzaldehyde derivatives were generated by the addition of CuCl and morpholine instead of Na2CO3. (Chemical Equation Presented).
Hattori, Tomohiro,Takakura, Ryoya,Ichikawa, Tomohiro,Sawama, Yoshinari,Monguchi, Yasunari,Sajiki, Hironao
p. 2737 - 2743
(2016/04/26)

Efficient E-Selective Transfer Semihydrogenation of Alkynes by Means of Ligand-Metal Cooperating Ruthenium Catalyst
The manuscript describes an efficient protocol for the E-selective transfer semihydrogenation of internal alkynes employing a previously described bifunctional ruthenium-based PC(sp3)P complex, 20'mol% of sodium formate and nearly stoichiometric formic acid. Semihydrogenation of the terminal alkynes results in the formation of the corresponding styrenes. The mechanism of the reaction includes stepwise transfer of both the hydride and the proton of the formic acid to the substrate. This fact allowed for the development of a facile protocol for the synthesis of monodeuterated alkenes by simply applying formic acid/sodium formate/D2O mixture as a hydrogen source. High yields, selectivity and functional group compatibility have been generally achieved.
Musa, Sanaa,Ghosh, Amrita,Vaccaro, Luigi,Ackermann, Lutz,Gelman, Dmitri
supporting information
p. 2351 - 2357
(2015/07/27)

REACTION CATALYST FOR CROSS COUPLING AND METHOD FOR MANUFACTURING AROMATIC COMPOUND
The object of the present invention is to provide a new organic phosphorus ligand that can efficiently promote cross-coupling reaction to obtain the target substance at high yield, as well as a method of manufacturing such ligand whose steric characteristics and electronic characteristics can be fine-tuned and which can be used to cause cross-coupling reaction at high yield. As a means for achieving the aforementioned object, a phosphine compound expressed by General Formula (1) below is provided. (In the formula, R1 and R2 are each independently a secondary alkyl group, tertiary alkyl group, or cycloalkyl group, while R3 and R4 are each independently a hydrogen, aliphatic group, heteroaliphatic group, aromatic group, alicyclic group, or heterocyclic group. Note that R3 and R4 have no phosphorus atom and that R3 and R4 are not both hydrogen at the same time).
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Paragraph 0074; 0075

(2015/12/18)

Wittig Reactions of Trialkylphosphine-derived Ylides: New Directions and Applications in Organic Synthesis
The development of semi-stabilized, stabilized, and functionalized ylides derived from short-chain trialkylphosphines in the Wittig-type olefination reactions toward the synthesis of alkenes, including stilbenes, styrenes, and 1,3-dienes, as well as reagents for homologation reactions, are described. The methods allow easy access to alkenes with high (E)-stereoselectivity in good yield. These reactions are conducted with weak bases in aqueous media, which allows easy separation of water-soluble phosphine oxides. The development of a mild organocatalytic process for the Wittig reaction and extension toward the preparation of reporter stilbenes under biological conditions are also described. Applications toward the preparation of biologically active natural products and derivatives are discussed.
McNulty, James,McLeod, David,Das, Priyabrata,Zepeda-Velázquez, Carlos
p. 619 - 632
(2016/01/15)

The Key Role of the Nonchelating Conformation of the Benzylidene Ligand on the Formation and Initiation of Hoveyda-Grubbs Metathesis Catalysts
Experimental studies of Hoveyda-Grubbs metathesis catalysts reveal important consequences of substitution at the 6-position of the chelating benzylidene ligand. The structural modification varies conformational preferences of the ligand that affects its exchange due to the interaction of the coordinating site with the ruthenium center. As a consequence, when typical S-chelated systems are formed as kinetic trans-Cl2 products, for 6-substituted benzylidenes the preference is altered toward direct formation of thermodynamic cis-Cl2 isomers. Activity data and reactions with tricyclohexylphosphine (PCy3) support also a similar scenario for O-chelated complexes, which display fast trans-Cl2?cis-Cl2 equilibrium observed by NMR EXSY studies. The presented conformational model reveals that catalysts, which cannot adopt the optimal nonchelating conformation of benzylidene ligand, initiate through a high-energy associative mechanism.
Bieszczad, Bartosz,Barbasiewicz, Micha?
supporting information
p. 10322 - 10325
(2015/07/07)

Diarylrhodates as promising active catalysts for the arylation of vinyl ethers with grignard reagents
Anionic diarylrhodium complexes, generated by reacting [RhCl(cod)] 2 with 2 equiv of aryl Grignard reagents, were found to be effective active catalysts in cross-coupling reactions of vinyl ethers with aryl Grignard reagents, giving rise to the production of vinyl arenes. In this catalytic system, vinyl-O bonds were preferably cleaved over Ar-O or Ar-Br bonds. A lithium rhodate complex was isolated, and its crystal structure was determined by X-ray crystallography.
Iwasaki, Takanori,Miyata, Yoshinori,Akimoto, Ryo,Fujii, Yuuki,Kuniyasu, Hitoshi,Kambe, Nobuaki
p. 9260 - 9263
(2014/07/21)

Room temperature hydrophosphination using a simple iron salen pre-catalyst
Phosphines are fundamentally important to the fine chemicals, pharmaceutical and agrochemical industries. Reported is the first example of alkene hydrophosphination using a designed iron pre-catalyst which yields the anti-Markovnikov products in high yield at room temperature. The phosphine products are excellent pro-ligands for Fe-catalyzed Negishi cross-coupling. This journal is
Gallagher,Webster
supporting information
p. 12109 - 12111
(2015/01/08)

Cis-specific hydrofluorination of alkenylarenes under palladium catalysis through an ionic pathway
This paper describes the hydrofluorination of alkenes through sequential H- and F+ addition under palladium catalysis. The reaction is cis specific, thus providing access to benzylic fluorides. The mechanism of this reaction involves an ionic pathway and is distinct from known hydrofluorinations involving radical intermediates. The first catalytic enantioselective hydrofluorination is also disclosed. See attached PdF: A series of benzylic fluorides was prepared by hydrofluorination which proceeds through a PdII/IV catalytic manifold. The method is mechanistically distinct from previously reported radical hydrofluorination, and is characterized by its clean regioselectivity and unique cis stereospecificity. The first example of enantioselective net HF addition onto 2-vinylnaphthalene is also disclosed.
Emer, Enrico,Pfeifer, Lukas,Brown, John M.,Gouverneur, Veronique
supporting information
p. 4181 - 4185
(2014/05/06)

Heck, Sonogashira, and Hiyama reactions catalyzed by palladium nanoparticles stabilized by tris-imidazolium salt
Palladium nanoparticles, prepared by the hydrogenation of Pd(dba) 2 in the presence of a tris-imidazolium iodide as stabilizer, act as an efficient catalyst for Heck and copper-free Sonogashira reactions with a range of aryl iodides and bromides at 0.2 mol-% Pd loading. Moreover, we describe a convenient protocol for the fluoride-free Hiyama coupling of vinylsilanes with aryl iodides that involves the use of sodium hydroxide as promoter in a methanol/water mixture. Under the developed conditions, one-pot, double Heck and Hiyama-Heck reactions are successfully achieved.
Planellas, Marc,Moglie, Yanina,Alonso, Francisco,Yus, Miguel,Pleixats, Roser,Shafir, Alexandr
supporting information
p. 3001 - 3008
(2014/05/20)

The synthesis of α-azidoesters and geminal triazides
Three simple methods for the synthesis of geminal triazides are described: Starting from 1) 3-oxocarboxylic acids, 2) iodomethyl ketones, or 3) terminal olefins, a range of triazidomethyl ketones can be constructed under mild oxidative reaction conditions by the use of IBX-SO3K, a sulfonylated derivative of 2-iodoxybenzoic acid (IBX), and NaN3 as an azide source. This is the first report of representatives of this novel class of triazide compounds: Despite their high nitrogen content, the geminal triazides are easy to handle, even when preparative-scale syntheses are performed. (Caution: These procedures still require protective measures!) The triazides are now broadly available for further studies regarding their properties and reactivity. Furthermore, we show how the method can be used to provide α-azidoesters, which are potential building blocks for amino acids. Either/or: Geminal triazides are rapidly constructed with broad scope by the use of oxocarboxylic acids, iodomethyl ketones, or terminal olefins as starting substrates in oxidative azidations with a mild derivative of 2-iodoxybenzoic acid and sodium azide. Along with this little-studied class of organic azides, α-azidoesters were also synthesized.
Klahn, Philipp,Erhardt, Hellmuth,Kotthaus, Andreas,Kirsch, Stefan F.
supporting information
p. 7913 - 7917
(2014/08/05)

Chemo-, Regio-, and stereoselective trifluoromethylation of styrenes via visible light-driven single-electron transfer (SET) and triplet-triplet energy transfer (TTET) processes
A process for tunable and chemo-, regio-, and stereoselective photocatalytic trifluoromethylation of styrenes was developed. Thermodynamically stable E-trifluoromethylated alkenes were prepared using Tognis reagent in the presence of Ru(bpy)3Cl2·6H2O under visible light irradiation, whereas less thermodynamically stable Z-trifluoromethylated alkenes were obtained by employing Umemotos reagent and photocatalyst Ir(ppy)3.
Lin, Qing-Yu,Xu, Xiu-Hua,Qing, Feng-Ling
p. 10434 - 10446
(2015/02/19)

Isomerizing ethenolysis as an efficient strategy for styrene synthesis
A shrinking chain: A bimetallic system consisting of [{Pd(μ-Br)(tBu 3P)}2] and a ruthenium metathesis catalyst has been found to efficiently promote the cross-metathesis between substituted alkenes and ethylene, while continuously migrating the double bond along the alkenyl chain (see scheme). When alkenylarenes, such as the natural products eugenol, safrol, or estragol, were treated with this catalyst under an ethylene atmosphere, they were cleanly converted into the corresponding styrenes and propylene gas. Copyright
Baader, Sabrina,Ohlmann, Dominik M.,Goossen, Lukas J.
supporting information
p. 9807 - 9810
(2013/08/23)

Resveratrol derived butyrylcholinesterase inhibitors
Novel polyhydroxylated (E)-stilbenes were synthesized by Mizoroki-Heck reactions and tested for their ability to inhibit the enzymes acetyl- and butyrylcholinesterase. Several of them are good inhibitors of butyrylcholinesterase; one of them carrying an extra fluorine substituent is a 94-fold stronger inhibitor of butyrylcholinesterase than of acetylcholinesterase. Novel polyhydroxylated (E)-stilbenes synthesized by Mizoroki-Heck reactions were tested for their ability to inhibit the enzymes acetyl- and butyrylcholinesterase. Several of them were found to be good inhibitors of butyrylcholinesterase. One of them carrying an extra fluorine substituent is a 94-fold stronger inhibitor of butyrylcholinesterase than of acetylcholinesterase.
Csuk, Rene,Albert, Sabrina,Kluge, Ralph,Stroehl, Dieter
p. 499 - 503
(2013/07/26)

Iron-catalyzed, highly regioselective synthesis of α-aryl carboxylic acids from styrene derivatives and CO2
The iron-catalyzed hydrocarboxylation of aryl alkenes has been developed using a highly active bench-stable iron(II) precatalyst to give α-aryl carboxylic acids in excellent yields and with near-perfect regioselectivity. Using just 1 mol % FeCl2, bis(imino)pyridine 6 (1 mol %), CO 2 (atmospheric pressure), and a hydride source (EtMgBr, 1.2 equiv), a range of sterically and electronically differentiated aryl alkenes were transformed to the corresponding α-aryl carboxylic acids (up to 96% isolated yield). The catalyst was found to be equally active with a loading of 0.1 mol %. Preliminary mechanistic investigations show that an iron-catalyzed hydrometalation is followed by transmetalation and reaction with the electrophile (CO2).
Greenhalgh, Mark D.,Thomas, Stephen P.
supporting information; experimental part
p. 11900 - 11903
(2012/09/07)

Ruthenium(IV)-catalyzed markovnikov addition of carboxylic acids to terminal alkynes in aqueous medium
The dimeric bis(allyl)ruthenium(IV) complex [{RuCl(μ-Cl)( η3:η3-C10H16)}2] (C10H16 = 2,7-dimethylocta-2,6-diene-1,8-diyl) (5) and several mononuclear species trans-[RuCl2(η3: η3-C10H16)(L)] (L = two-electron-donor ligand) (6) derived from 5 have been checked as catalysts for the addition of carboxylic acids onto terminal alkynes using water as a green reaction medium. The best results in terms of activity and regioselectivity were obtained with the mononuclear derivative trans-[RuCl2(η3: η3-C10H16)(PPh3)] (6a), which was able to promote the selective Markovnikov addition of both aromatic and aliphatic carboxylic acids to a large variety of terminal alkynes, enynes, and diynes as well as propargylic alcohols. In this way, a wide number of enol esters and β-oxo esters could be synthesized in moderate to good yields under mild conditions (60 °C) in an aqueous medium.
Cadierno, Victorio,Francos, Javier,Gimeno, Jose
experimental part
p. 852 - 862
(2011/04/15)

A direct synthesis of functionalized styrenes and terminal 1,3-dienes via aqueous Wittig chemistry with formalin
A direct synthesis of functionalized styrenes including synthetically valuable styryl halides and terminal 1,3-dienes is reported directly from benzylic and allylic alcohols and aqueous formalin involving microwave assisted phosphonium salt formation and Wittig olefination under mildly basic conditions.
Das, Priyabrata,McLeod, David,McNulty, James
experimental part
p. 199 - 201
(2011/02/26)

α-Selective Ni-catalyzed hydroalumination of aryl- and alkyl-substituted terminal alkynes: Practical syntheses of internal vinyl aluminums, halides, or boronates
A method for Ni-catalyzed hydroalumination of terminal alkynes, leading to the formation of α-vinylaluminum isomers efficiently (>98% conv in 2-12 h) and with high selectivity (95% to >98% α), is described. Catalytic α-selective hydroalumination reactions proceed in the presence of a reagent (diisobutylaluminum hydride; dibal-H) and 3.0 mol % metal complex (Ni(dppp)Cl2) that are commercially available and inexpensive. Under the same conditions, but with Ni(PPh3)2Cl2, hydroalumination becomes highly β-selective, and, unlike uncatalyzed transformations with dibal-H, generates little or no alkynylaluminum byproducts. All hydrometalation reactions are reliable, operationally simple, and practical and afford an assortment of vinylaluminums that are otherwise not easily accessible. The derived α-vinyl halides and boronates can be synthesized through direct treatment with the appropriate electrophiles [e.g., Br 2 and methoxy(pinacolato)boron, respectively]. Ni-catalyzed hydroaluminations can be performed with as little as 0.1 mol % catalyst and on gram scale with equally high efficiency and selectivity.
Gao, Fang,Hoveyda, Amir H.
supporting information; experimental part
p. 10961 - 10963
(2010/09/17)

Challenges associated with the synthesis of unusual o-carboxamido stilbenes by the Heck protocol: Intriguing substituent effects, their toxicological and chemopreventive implications
The syntheses of fourteen unusual o-carboxamido stilbenes by the Heck protocol revealed surprising complexity related to intriguing substituent effects with mechanistic implications. The unexpected cytotoxic and chemopreventive properties also seem to be substituent dependent. For example, although stilbene 15d (with a 4-methoxy substituent) showed cytotoxicity on HT29 colon cancer cells with an IC50 of 4.9 μM, the 3,4-dimethoxy derivative (15c) is inactive. It is interesting to observe that the 3,5-dimethoxy derivative (15e) showed remarkable chemopreventive activity in WRL-68 fetal hepatocytes, surpassing the gold standard, resveratrol. The resveratrol concentration needed to be 5 times higher than that of 15e to produce comparable elevation of NQO1.
Kee, Chin Hui,Ariffin, Azhar,Awang, Khalijah,Takeya, Koichi,Morita, Hiroshi,Hussain, Salmaan Inayat,Chan, Kok Meng,Wood, Pauline J.,Threadgill, Michael D.,Lim, Chuan Gee,Ng, Seikweng,Weber, Jean Frederic F.,Thomas, Noel F.
experimental part
p. 5646 - 5660
(2011/02/18)

Nickel-catalyzed vinylation of aryl chlorides and bromides with vinyl ZnBr · MgBrCl
The Ni-catalyzed cross-coupling of aryl halides and vinylzinc bromide for the synthesis of styrene derivatives was investigated. Of the catalysts surveyed, the combination of Ni(acac)2 and Xantphos was found to be the most effective for this cr
Yamamoto, Tetsuya,Yamakawa, Tetsu
supporting information; experimental part
p. 3603 - 3605
(2009/09/06)

Gold and palladium combined for cross-coupling
Gold and palladium-a unique liason: A study of the transmetalation abilities of organogold compounds builds the basis for a new class of cross-coupling reactions. Stable intermediates of gold catalysis deliver new complex products by a palladium-catalyzed coupling reaction, (see Scheme)
Hashmi, A. Stephen K.,Lothschuetz, Christian,Doepp, Rene,Rudolph, Matthias,Ramamurthi, Tanuja D.,Rominger, Frank
supporting information; experimental part
p. 8243 - 8246
(2010/02/27)

Vinylation of aromatic halides using inexpensive organosilicon reagents. Illustration of design of experiment protocols
The preparation of styrenes by palladium-catalyzed cross-coupling of aromatic iodides and bromides with divinyltetramethyldisiloxane (DVDS) in the presence of inexpensive silanolate activators has been developed. To facilitate the discovery of optimal reaction conditions, Design of Experiment (DoE) protocols were used. By the guided selection of reagents, stoichiometries, temperatures, and solvents, the vinylation reaction was rapidly optimized with three stages consisting of ca. 175 experiments (of a possible 1440 combinations). A variety of aromatic iodides undergo cross-coupling at room temperature in the presence of potassium trimethylsilanoate using Pd(dba) 2 in DMF in good yields. Triphenylphosphine oxide is needed to extend catalyst lifetime. Application of these conditions to aryl bromides was accomplished by the development of two complementary protocols. First, the direct implementation of the successful reaction conditions using aryl iodides at elevated temperature in THF provided the corresponding styrenes in good to excellent yields. Alternatively, the use of potassium triethylsilanolate and a bulky "Buchwald-type" ligand allows for the vinylation reactions to occur at or just above room temperature. A wide range of bromides underwent coupling in good yields for each of the protocols described.
Denmark, Scott E.,Butler, Christopher R.
p. 3690 - 3704
(2008/10/09)

Preparation of nonsymmetrically substituted stilbenes in a one-pot two-step Heck strategy using ethene as a reagent
(Chemical Equation Presented) We present here a strategy for the preparation of nonsymmetrically substituted stilbenes using a one-pot two-step double Heck strategy. First a protocol is developed for the selective preparation of a range of styrenes using ethene as the alkene coupling partner. Then conditions are found for the effective coupling of the styrenes with aryl halides using a 1:1 stoichiometric ratio of the two components. The use of the microwave apparatus to perform the reactions offers a convenient method for synthesis as well as for safely, easily, and accurately loading vessels with gaseous reagents.
Kormos, Chad M.,Leadbeater, Nicholas E.
p. 3854 - 3858
(2008/09/19)

Vinylation of aryl bromides using an inexpensive vinylpolysiloxane
(Chemical Equation Presented) A mild and general method for the palladium-catalyzed vinylation of aryl bromides has been developed. The use of tetrabutylammonium fluoride (TBAF) as the activator and an inexpensive and nontoxic vinyl donor, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane (D4V, 1), allows for a general and high-yielding preparation of substituted styrenes.
Denmark, Scott E.,Butler, Christopher R.
p. 63 - 66
(2007/10/03)

Suzuki-Miyaura cross-coupling reactions of potassium vinyltrifluoroborate with aryl and heteroaryl electrophiles
We have previously reported that the palladium-catalyzed cross-coupling reaction of potassium vinyltrifluoroborate with aryl electrophiles proceeds with good yields. Herein, we describe recent progress in optimizing the reaction, as well as outlining the scope and limitations of the reaction. The cross-coupling reaction can generally be effected using 2 mol % of PdCl2 and 6 mol % of PPh3 as a catalyst system in THF/H2O with Cs 2CO3 as a base. Moderate to good yields are obtained in the presence of a variety of functional groups.
Molander, Gary A.,Brown, Adam R.
p. 9681 - 9686
(2007/10/03)

Novel anti-Markovnikov regioselectivity in the Wacker reaction of styrenes
The Wacker reaction is one of the longest known palladium-catalysed organic transformations, and in the vast majority of cases proceeds with Markovnikov regioselectivity. Palladium(II)-mediated oxidation of styrenes was examined and in the absence of reoxidants was found to proceed in an anti-Markovnikov sense, giving aldehydes. Studies on the mechanism of this unusual transformation were carried out, and indicate the possible involvement of a η4-palladium-styrene complex. With a heteropolyacid as the terminal oxidant, oxidation of styrene to give the anti-Markovnikov aldehyde as the major product was found to be catalytic.
Wright, Joseph A.,Gaunt, Matthew J.,Spencer, Jonathan B.
p. 949 - 955
(2007/10/03)