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Hydrocarboxylation of alkynes with formic acid over multifunctional ligand modified Pd-catalyst with co-catalytic effect
Hydrocarboxylation of terminal alkynes with formic acid (FA) was accomplished over a multifunctional ligand (L2) modified Pd-catalyst, advantageous with 100% atom-economy, free use of CO and H2O, mild reaction conditions, and high yields (56–89%) of α,β-unsaturated carboxylic acids with 100% regioselectivity to the branched ones. The multifunctional ligand of L2 as a zwitterion salt containing the phosphino-fragment (-PPh2), Lewis acidic phosphonium cation and sulfonate group (-SO3?), was constructed on the skeleton of 1.1′-binaphthyl-2.2′-diphenyl phosphine (BINAP) upon selective quaternization by 1,3-propanesultone. It was found that L2 conferred to the Pd-catalyst the co-catalytic effect, wherein the phosphino-coordinated Pd-complex was responsible for activation of all the substrates (including CO, FA and alkyne), and the incorporated phosphonium cation was responsible for synergetic activation of FA. The 1H NMR spectroscopic analysis supported that FA was truly activated by the incorporated Lewis acidic phosphonium cation in L2 via “acid-base pair” interaction. The in situ FT-IR spectra demonstrated that, the presence of Ac2O and NaOAc additives in the catalytic amount could dramatically promote the in situ release of CO from FA, which was required to initiate the hydrocarboxylation.
Chen, Xiao-Chao,Guo, Lin,Liu, Lei,Liu, Ye,Lu, Yong,Yao, Yin-Qing,Zhao, Xiao-Li
p. 322 - 332
(2022/01/06)

Click amidations, esterifications and one–pot reactions catalyzed by Cu salts and multimetal–organic frameworks (M–MOFs)
Amides and esters are prevalent chemicals in Nature, industry and academic laboratories. Thus, it is not surprising that a plethora of synthetic methods for these compounds has been developed along the years. However, these methods are not 100% atom economical and generally require harsh reagents or reaction conditions. Here we show a “spring–loaded”, 100% atom–efficient amidation and esterification protocol which consists in the ring opening of cyclopropenones with amines or alcohols. Some alkyl amines react spontaneously at room temperature in a variety of solvents and reaction conditions, including water at different pHs, while other alkyl amines, aromatic amines and alcohols react in the presence of catalytic amounts of simple Cu2+ salts or solids. A modular reactivity pattern (alkyl amines >> alkyl alcohols >> phenols >> aromatic amines) enables to design orthogonal and one–pot reactions on well–defined catalytic Multimetal–Organic Frameworks (M–MOFs, M= Cu, Ni, Pd), to easily functionalize the resulting cinnamides and cinnamic esters to more complex molecules. The strong resemblance of the amidation and esterification reaction conditions here reported with the copper–catalyzed azide–alkyne cycloaddition (CuAAC) allows to define this fast, clean and flexible protocol as a click reaction.
Armentano, Donatella,Ferrando-Soria, Jesús,Greco, Rossella,Leyva-Pérez, Antonio,Palomar-De Lucas, Brenda,Pardo, Emilio,Tiburcio, Estefanía
(2022/03/17)

Access to α,β-unsaturated carboxylic acids through water-soluble palladium catalyzed hydroxycarbonylation of alkynes using water as the solvent
A sulfoxantphos modified palladium-catalyzed synthesis of α,β-unsaturated carboxylic acids from alkynes with CO and H2O was described. The atom-economic hydroxycarbonylation of various symmetrical and unsymmetrical alkynes can be achieved with chemo-, stereo-, and regioselectivity, affording the corresponding carboxylic acids in good to excellent yields. Using water as the reaction solvent, the water-soluble palladium catalyst was easily separated from the product and could be reused for 5 cycles.
Gao, Mingjie,Jia, Xiaofei,Lv, Jinhe,Ren, Xinyi,Song, Jiaxin,Xie, Congxia,Zhang, Jinrong,Zhang, Kai,Zhao, Jinyu,Zhou, Ziqin,Zong, Lingbo
p. 4708 - 4713
(2021/07/26)

Palladium catalyzed 8-aminoimidazo[1,2-: A] pyridine (AIP) directed selective β-C(sp2)-H arylation
Palladium catalyzed arylation of the inert β-C(sp2)-H bond of carboxylic acid derivatives is reported herein for the first time utilizing 8-aminoimidazo[1,2-a]pyridine (AIP) as an efficacious and new inbuilt 6,5-fused bicyclic removable directing group. This protocol is scalable, exhibits high levels of β-site selectivity and tolerates a broad spectrum of functional groups. This journal is
Mondal, Biswajit,Ghosh, Prasanjit,Kundu, Mrinalkanti,Das, Tapas Kumar,Das, Sajal
p. 360 - 364
(2021/01/29)

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)

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.
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Paragraph 0103-0104; 0527-0531

(2021/05/05)

Novel stilbene scaffolds efficiently targetMycobacterium tuberculosisnucleoid-associated protein, HU
Novel scaffolds of stilbene were identified as inhibitors ofMycobacterium tuberculosisby targeting the nucleoid-associated protein, HU, using molecular docking. Based on the proposed combinatorial libraries I to VI, structures I and III had significantly greater docking binding energy that was comparable to that of the reference ligand, protein HU, fromMycobacterium tuberculosis.Using these docking results, 18 compounds were synthesized, characterized and evaluated forin vitroantitubercular (anti-TB) efficacy in theMycobacterium tuberculosisstrain, H37Rv. Thein vitroscreening results indicated a significant positive correlation between the docking binding efficacy (r2> 0.5) and clogp. Compounds3f,3dand4fwere ranked as top scoring ligands that interacted with amino acids ARG 53, ARG 55, PRO 81, PHE 79, and LYS 13, where the -NO2or -Cl substitution at theparaposition of the 3-phenyl ring was essential for interacting of the HU protein. The hydrogen bonding with ARG 55 and LYS 13 of these compounds was similar to that with the reference ligand that inhibits the HUMtbprotein. Compounds3d,3f, and4fwere evaluated as active leads, with MIC90 values of 21.3, 23.2 and 44.1 μM, respectively. The above mentioned compounds were also evaluated for antibacterial and antifungal efficacy in a panel of selected bacteria and fungi. Compound3dhad efficacy (MIC90: 6.82 μM) inS. aureusandE. coli. Compound3fwas also efficacious inE. coliandA. Niger, with an MIC90 value of 7.42 μM for both microorganisms. The fluoro-phenyl derivatives,3iand4i, were efficacious inC. albicans(MIC90 values of 8.2 and 7.8 μM, respectively) andA. niger(MIC90 values of 4.1 and 3.1 μM, respectively). Our results suggest that substitutions at theparaposition of 3-phenyl acryl derivatives with -NO2and -Cl significantly affected the binding interactions with the HUMtb protein in the docking studies. Furthermore these compounds had antitubercular and antimicrobial efficacy. The substituted phenyl acrylic acid and hydrazides could be inhibitors of the HUMtb protein ofMycobacterium tuberculosis.
Peraman, Ramalingam,Meka, Geethavani,Chilamakuru, Naresh Babu,Kutagulla, Vinay Kumar,Malla, Saloni,Ashby, Charles R.,Tiwari, Amit K.,Yiragamreddy, Padmanabha Reddy
p. 10683 - 10692
(2021/06/27)

Stereospecific Electrophilic Fluorocyclization of α,β-Unsaturated Amides with Selectfluor
An efficient fluorocyclization of α,β-unsaturated amides through a formal halocyclization process is developed. The reaction proceeds under transition-metal-free conditions and leads to the formation of fluorinated oxazolidine-2,4-diones with excellent regio- and diastereoselectivity. The evaluation of the reaction mechanism based on preliminary experiments and density functional theory calculations suggests that a synergetic syn-oxo-fluorination occurs and is followed by an anti-oxo substitution reaction. The reaction opens a new window in the field of stereospecific fluorofunctionalization.
Fei, Haiyang,Fu, Yao,Jalani, Hitesh B.,Li, Guigen,Lu, Hongjian,Wu, Hongmiao,Xu, Zheyuan,Zhu, Lin
(2020/03/30)

Method for synthesizing alpha-acrylic acid compound by catalyzing carbon dioxide and alkyne with palladium
The invention belongs to the technical field of organic synthesis, and discloses a method for synthesizing an alpha-acrylic acid compound by catalyzing carbon dioxide and alkyne with palladium. The preparation method comprises the following steps: adding an alkyne compound, a palladium salt catalyst, alkali, a diphosphine ligand, a silane reducing agent and a solvent into a high-pressure reactionkettle, introducing carbon dioxide, stirring and reacting at 60-120 DEG C, washing a reaction liquid with water for extraction, and separating for purification to obtain the alpha-acrylic acid compound. By using the palladium salt as the catalyst and the diphosphine ligand as the ligand, the method has the characteristics of high yield, single selectivity, wide substrate applicability and the like. In addition, by taking the alkyne compound and carbon dioxide as raw materials in the reaction, the method has the advantages as follows: the raw materials are simple and easily available, the operation is simple and convenient and the atom economy is high.
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Paragraph 0117-0123

(2020/05/02)

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
p. 2080 - 2088
(2020/02/20)

Macrolactam Synthesis via Ring-Closing Alkene-Alkene Cross-Coupling Reactions
Reported herein is a practical method for macrolactam synthesis via a Rh(III)-catalyzed ring closing alkene-alkene cross-coupling reaction. The reaction proceeded via a Rh-catalyzed alkenyl sp2 C-H activation process, which allows access to macrocyclic molecules of different ring sizes. Macrolactams containing a conjugated diene framework could be easily prepared in high chemoselectivities and Z,E stereoselectivities.
Goh, Jeffrey,Loh, Teck-Peng,Maraswami, Manikantha
supporting information
p. 9724 - 9728
(2020/12/21)

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)

Targeting inflammation with conjugated cinnamic amides, ethers and esters
Background: Cinnamic acid is a key intermediate in shikimate and phenylpropanoid pathways. It is found both in free form, and especially in the form of esters in various essential oils, resins and balsams which are very important intermediates in the biosynthetic pathway of several natural products. The cinnamic derivatives play a vital role in the formation of commercially important intermediate molecules which are necessary for the production of different bioactive compounds and drugs. Different substitutions on basic moiety lead to various biological activities. Furthermore, combination of appropriate pharmacophore groups with cinnamic acid derivatives were developed to give hybrids in order to find out promising drug candidates as inhibitors of multiple biological targets associated with inflammation. We found interesting to continue our efforts to design and synthesise three series of novel cinnamic acid-based hybrids: a) nitrooxy esters of cinnamic acid, b) ethers and c) amides of cinnamic acids with arginine, as pleiotropic candidates against multiple targets of inflammation Methods: The synthesis of cinnamic was established by a Knoevenagel-Doebner condensation of the suitable aldehyde either with malonic acid in the presence of pyridine and piperidine, or with phenylacetic acid in the precence of triethylamine in acetic anhydride. The synthesis of the corresponding esters was conducted in two steps. The ethers were synthesized in low yields, with 1,2 – dibromoethane in dry acetone, in the presence of K2CO3, to give oily products. The corresponding cinnamic amides were synthesised in a single step. The synthesised hybrids were tested as lipoxygenase (LOX) and cyclooxygenase (COX) inhibitors in vitro. In silico docking was applied to all the novel derivatives. Several molecular properties of the hybrids were calculated in order to evaluate their drug likeness. Results: A number of esters, ethers and amides of selected cinnamic acids, either phenyl substituted or not, has been synthesised and subjected to modelling studies. The compounds were studied in vitro/in vivo for their inhibitory activities on cox and lox, and as antioxidants. Log P values of all the title compounds except of 3a (5.38) were found to be less than 5 and are in agreement to Lipinski’s rule of five, suggesting satisfactory permeability across cell membrane. The molecular modelling study seems to be in accordance with the experimental results for LOX and COX-2. The result of antioxidant activity for amide 3b supports the anti-lox activity. Compound 5d presents the higher in vivo anti-inflammatory. Conclusion: According to the experimental findings compounds 3b and 5d can be used as lead compounds for the design of new molecules to target inflammation.
Fotopoulos, Ioannis,Litina, Dimitra Hadjipavlou,Pontiki, Eleni
p. 3 - 11
(2020/02/06)

Electrocatalytic asymmetric hydrogenation of α,β-unsaturated acids in a PEM reactor with cinchona-modified palladium catalysts
We have developed an electrocatalytic asymmetric hydrogenation reaction using a proton-exchange membrane (PEM) reactor that employs a polymer electrolyte fuel cell and industrial electrolysis technologies. Reasonable enantioselectivities and excellent current efficiencies were obtained in the asymmetric hydrogenation of α-phenylcinnamic acid under mild conditions without adding a supporting electrolyte. The current density was crucial to achieving the improved results observed.
Atobe, Mahito,Fukazawa, Atsushi,Hashimoto, Yasushi,Sato, Yasushi,Tanaka, Kenta
(2020/04/28)

Nickel nanoparticle-catalyzed carboxylation of unsaturated hydrocarbon with CO2 using sulfur-modified Au-supported nickel material
A hydrocarboxylation reaction of alkyne or styrene derivatives with CO2 proceeded smoothly by using an air-stable nano-sized nickel catalyst supported on sulfur-modified gold (SANi), giving functionalized acrylic acids and phenylpropionic acids including an anti-inflammatory drug, Flurbiprofen. Notably, SANi could be recycled several times without a significant decrease of the yield.
Taniguchi, Takahisa,Saito, Nozomi,Doi, Ryohei,Kimoto, Arato,Hoshiya, Naoyuki,Fujiki, Katsumasa,Shuto, Satoshi,Fujioka, Hiromichi,Arisawa, Mitsuhiro,Sato, Yoshihiro
supporting information
p. 1406 - 1409
(2019/11/05)

Design, synthesis, and biological evaluation of compounds with a new scaffold as anti-neuroinflammatory agents for the treatment of Alzheimer's disease
Twenty-eight compounds with a new scaffold were designed and synthesized by assembling fragments derived from known agents such as stilbenes and piperazinyl pyrimidines. Many strategies have been explored to improve the druggability of these series of compounds, such as increasing the distance between two benzene rings in the scaffold and introducing functional groups at designated positions. These compounds were validated for their anti-neuroinflammatory activity in BV2 cells. Experimental results reveal that the most active compound 8b can inhibit nitric oxide (NO), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) production with IC50 values of 1.0, 2.6, and 0.5 μM, respectively. The compound can also significantly modulate the MAPK pathways through inhibiting the phosphorylation of JNK, ERK1/2, and p38 MAPK without disturbing NF-κB pathway. Parallel artificial membrane permeation assay demonstrated that the most active compound can overcome the blood-brain barrier (BBB). Therefore, this compound can be a promising lead for the treatment of Alzheimer's disease.
Fang, Yuying,Xia, Wenjuan,Cheng, Bao,Hua, Pei,Zhou, Huihao,Gu, Qiong,Xu, Jun
p. 129 - 138
(2018/03/06)

Anti-neuroinflammatory stilbene analogues as well as preparation method and application thereof
The invention provides anti-neuroinflammatory stilbene analogues as well as a preparation method and an application thereof. The anti-neuroinflammatory stilbene analogues have the structure as followsin the description, wherein R1 is H, halogeno, C1-C5 saturated straight chain alkyl and C1-C3 saturated straight chain alkyl substituted by one or more halogen atoms; and R2 is H, O(CH2)mCH3, halogen, hydroxyl, C1-C5 saturated straight chain alkyl and C1-C3 saturated straight chain alkyl substituted by one or more halogen atoms. According to a lead compound discovery method based on molecular assembly, a new skeleton molecule is designed by assembling two fragments of pyrimidine piperazine and stilbene, and a series of stilbene analogues are synthesized. The compounds have significant anti-neuroinflammatory activity, can permeate blood-brain barrier and can be used as a lead compound in treatment of senile dementia.
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Paragraph 0028; 0031; 0032

(2018/09/08)

Following palladium catalyzed methoxycarbonylation by hyperpolarized NMR spectroscopy: A: para hydrogen based investigation
Pd(OTf)2(bcope) is shown to react in methanol solution with diphenylacetylene, carbon monoxide and hydrogen to produce the methoxy-carbonylation product methyl 2,3 diphenyl acrylate alongside cis- and trans-stilbene. In situ NMR studies harnessing the parahydrogen induced polarization effect reveal substantially enhanced 1H NMR signals in both protic and aprotic solvents for a series of reaction intermediates that play a direct role in this homogeneous transformation. Exchange spectroscopy (EXSY) measurements reveal that the corresponding CO adducts are less reactive than their methanol counterparts.
Guan, Dexin,Jonathan Holmes,López-Serrano, Joaquín,Duckett, Simon B.
p. 2101 - 2109
(2017/07/15)

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)

Novel and practical asymmetric synthesis of β2,3-amino esters using asymmetric Michael addition of chiral amine
A practical method for the synthesis of chiral β2,3-amino esters having various substituents was developed, which is characterized by an asymmetric Michael addition reaction of a chiral lithium amide with trisubstituted (E)-α,β-unsaturated esters. We found that a highly face-selective protonation occurred by the quick addition of water to the enolate intermediate derived from the Michael addition reaction to afford N-protected β2,3-amino esters in moderate to excellent yields. This finding was made possible by the facile preparation of geometrically pure trisubstituted (E)-α,β-unsaturated esters, which was established recently by our group. The subsequent deprotection of the amino group in the Michael adduct by using N-iodosuccinimide (NIS) efficiently provided β2,3-amino esters having various substituents.
Ozeki, Minoru,Egawa, Honoka,Takano, Toshiki,Mizutani, Hideki,Yasuda, Narumi,Arimitsu, Kenji,Kajimoto, Tetsuya,Hosoi, Shinzo,Iwasaki, Hiroki,Kojima, Naoto,Node, Manabu,Yamashita, Masayuki
supporting information
p. 2014 - 2021
(2017/03/20)

Preparation method of alpha, beta-unsaturated carboxylic acid compounds
The invention provides a preparation method of alpha, beta-unsaturated carboxylic acid compounds. The method is characterized in that compounds represented by formula (I) react with formic acid in the presence of a nickel-containing catalyst, a phosphine ligand and an organic solvent to obtain the alpha, beta-unsaturated carboxylic acid compounds represented by formula (II), wherein R1 and R2 are respectively independently selected from H, C1-C30 alkyl groups, C1-C30 substituted alkyl groups, C1-C30 alkenyl groups, C1-C30 substituted alkenyl groups, C6-C30 aryl groups and C6-C30 substituted aryl groups. Compared with the prior art, the method adopting formic acid as a carboxylation reagent has the advantages of low price, safety, stability, low toxicity, high yield, simple operation, good economy, avoiding of use of precious metal catalysts and toxic gas carbon monoxide, meeting of requirements of environmentally friendly compounds, wide function group compatibility, high conversion rate and industrial synthesis values.
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Paragraph 0054; 0055; 0056; 0057; 0058; 0059

(2016/10/07)

Synthesis of Vinyl Carboxylic Acids using Carbon Dioxide as a Carbon Source by Iron-Catalyzed Hydromagnesiation
An iron-catalyzed synthesis of α,β-unsaturated carboxylic acids from alkynes and carbon dioxide was developed. This reaction proceeds through hydromagnesiation of alkynes followed by carbon dioxide insertion under atmospheric pressure and ambient temperature in the presence of iron and a Grignard reagent as a catalyst and hydride source, respectively. Several symmetrical and unsymmetrical alkynes were transformed into the corresponding acids in good to excellent yields. The methodology provides an efficient route to the synthesis of vinyl carboxylic acids.
Santhoshkumar, Rajagopal,Hong, Ya-Chun,Luo, Ching-Zong,Wu, Yun-Ching,Hung, Chen-Hsun,Hwang, Kuen-Yuan,Tu, An-Pang,Cheng, Chien-Hong
p. 2210 - 2213
(2016/07/19)

Palladium-Catalyzed Hydrocarboxylation of Alkynes with Formic Acid
A palladium-catalyzed hydrocarboxylation of alkynes with formic acid has been developed. The method provides acrylic acid and derivatives in good yields with high regioselectivity without the need to handle toxic CO gas. Nontoxic: Acrylic acids are an important chemical feedstock. The title reaction provides acrylic acid and derivatives in good yields with high regioselectivities without the need to handle toxic CO gas.
Hou, Jing,Xie, Jian-Hua,Zhou, Qi-Lin
supporting information
p. 6302 - 6305
(2015/05/20)

Systematic methodology for the development of biocatalytic hydrogen-borrowing cascades: Application to the synthesis of chiral α-substituted carboxylic acids from α-substituted α,β-unsaturated aldehydes
Ene-reductases (ERs) are flavin dependent enzymes that catalyze the asymmetric reduction of activated carbon-carbon double bonds. In particular, α,β-unsaturated carbonyl compounds (e.g. enals and enones) as well as nitroalkenes are rapidly reduced. Conversely, α,β-unsaturated esters are poorly accepted substrates whereas free carboxylic acids are not converted at all. The only exceptions are α,β-unsaturated diacids, diesters as well as esters bearing an electron-withdrawing group in α- or β-position. Here, we present an alternative approach that has a general applicability for directly obtaining diverse chiral α-substituted carboxylic acids. This approach combines two enzyme classes, namely ERs and aldehyde dehydrogenases (Ald-DHs), in a concurrent reductive-oxidative biocatalytic cascade. This strategy has several advantages as the starting material is an α-substituted α,β-unsaturated aldehyde, a class of compounds extremely reactive for the reduction of the alkene moiety. Furthermore no external hydride source from a sacrificial substrate (e.g. glucose, formate) is required since the hydride for the first reductive step is liberated in the second oxidative step. Such a process is defined as a hydrogen-borrowing cascade. This methodology has wide applicability as it was successfully applied to the synthesis of chiral substituted hydrocinnamic acids, aliphatic acids, heterocycles and even acetylated amino acids with elevated yield, chemo- and stereo-selectivity. A systematic methodology for optimizing the hydrogen-borrowing two-enzyme synthesis of α-chiral substituted carboxylic acids was developed. This systematic methodology has general applicability for the development of diverse hydrogen-borrowing processes that possess the highest atom efficiency and the lowest environmental impact. This journal is
Knaus, Tanja,Mutti, Francesco G.,Humphreys, Luke D.,Turner, Nicholas J.,Scrutton, Nigel S.
p. 223 - 233
(2015/02/19)

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)

Synthesis of 2-(hetero)aryl-5-(trimethylsilylethynyl)oxazoles from (hetero)arylacrylic acids
A three-step method for the synthesis of 2-(hetero)aryl-5-(trimethylsilylethynyl)oxazoles is described. Easily accessible bis(trimethylsilyl)acetylene and acrylic acid derivatives are used as starting materials for the preparation of mono- and disubstituted 5-(trimethylsilyl)pent-1-en-4-yn-3-ones. Oxidative phthalimidoaziridination of these enynones provides the key 2-acyl-1-phthalimidoaziridines that are further utilized in the thermal expansion of the three-membered ring to furnish the target functionalizable oxazoles.
Pankova, Alena S.,Stukalov, Alexander Yu.,Kuznetsov, Mikhail A.
p. 1826 - 1829
(2015/04/27)

Surface enhanced Raman spectroscopic (SERS) behavior of substituted propenoic acids used in heterogeneous catalytic asymmetric hydrogenation
The strength and geometry of adsorption of substituted propenoic acids on silver surface were studied by means of surface enhanced Raman spectroscopy (SERS) using silver sol. Based on their SERS behavior, two classes of phenylpropenoic acids studied were distinguished. The first class of propenoic acids (atropic acid, (E)-2,3-diphenylpropenoic acid, (E)-2-(2-methoxyphenyl)-3-phenylpropenoic acid, (E)-2,3-di-(4-methoxyphenyl)phenylpropenoic acid and (E)-2-(2-methoxyphenyl)-3-(4-fluorophenyl)propenoic acid) has shown strong charge transfer (CT) effect. We suggest bidentate carboxyl bonded species based on the SERS enhanced bands of νCOO- around 1394 cm-1 and νC-C of the -C-COO- moiety at 951 cm-1. In these series the plane of the α-phenyl group (γCH out-of-plane vibrations at 850-700 cm-1) is almost parallel to the silver surface, while the β-phenyl group is in tilted position depending on the type and the position of substituent(s) showing strong SERS enhanced bands of νCC + βCH (in-plane mode) at 1075 cm-1, νCC (ring breathing mode, in-plane) at 1000 cm-1 and γCCC (out-of-plane mode) around 401 cm-1. The other class of propenoic acids (cinnamic acid, (E)-2-phenyl-3-(4-methoxyphenyl)propenoic acid) has shown weak electromagnetic (EM) enhancement (CC bands is enhanced in cinnamic acid). In this case no significant carboxyl enhancement was observed, so we suggest that adsorbed species lie parallel to the surface. The two types of adsorption can be related to the dissociation ability of the carboxylic group. In the first case the carboxylic H dissociates, while in the second case it does not, as indicated also by the characteristic νCO band at 1686 cm-1 in the FT-Raman spectra of methanolic solutions.
Firkala, Tams,Tlas, Emlia,Kristyn, Sndor,Sz?ll'si, Gy?rgy,Drotr, Eszter,Mink, Jnos,Mihly, Judith
p. 1102 - 1109
(2016/01/26)

GUANIDINE DERIVATIVES AS TRPC MODULATORS
The present invention is directed to guanidine derivatives as inhibitors of transient receptor potential canonical channels (TRPC channels), in particular TRPC3 and/or TRPC6 and/or TRPC7 activity, more particularly TRPC6 activity. Also provided herein are processes for preparing compounds described herein, intermediates used in their synthesis, pharmaceutical compositions thereof, and methods for treating or preventing diseases, conditions and/or disorders mediated by TRPC channels (Formula (I))
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Page/Page column 42-43

(2014/02/16)

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)

Alkyne and reversible nitrile activation: N, N'-diamidocarbene-facilitated synthesis of cyclopropenes, cyclopropenones, and azirines
We report the synthesis of a variety of diamidocyclopropenes by combining an isolable and readily accessible N,N'-diamidocarbene (DAC) with a range of alkynes (nine examples, 68-97% yield). Subsequent hydrolysis of selected cyclopropenes afforded the corresponding cyclopropenones or α,β- unsaturated acids, depending on the reaction conditions. In addition, the combination of a DAC with alkyl or aryl nitriles was found to form 2H-azirines in a reversible manner (four examples, Keq = 4-72 M-1 at 30 °C in toluene).
Moerdyk, Jonathan P.,Bielawski, Christopher W.
supporting information; experimental part
p. 6116 - 6119
(2012/05/07)

Heterogeneous enantioselective hydrogenation of hydroxy-substituted (E)-2,3-diphenylpropenoic acids over Pd/Al2O3 modified by cinchonidine
The enantioselective hydrogenation of (E)-2,3-diphenylpropenoic acids substituted by hydroxyl group has been studied over Pd/Al2O 3 catalyst modified by cinchonidine. The effect of the acidic hydroxyl substituents was compared with that of the methoxy group in the same position. The para-hydroxyl substituent on the 3-phenyl ring had similar effect on the enantioselectivity as the methoxy group, whereas the meta positioned decreased the optical purity of the saturated acid. This was explained by different origin of the increase in the enantioselectivity obtained in the presence of electron releasing substituents in these positions. Although, the para-hydroxyl group on the 2-phenyl ring had beneficial influence on the enantioselectivity of the hydrogenation of the mono-substituted acid, in the presence of fluorine or hydroxyl group on the 3-phenyl ring the effect of the two substituents was not additive. This study demonstrated that the cinchonidine-modified Pd catalyst is appropriate for the preparation of several hydroxy-substituted 2,3-diphenylpropionic acids in good optical purities, extending the scope of this catalytic system to new types of versatile chiral building blocks.
Sz?ll?si, Gyo?rgy
experimental part
p. 345 - 351
(2012/06/18)

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
scheme or table
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)

Synthesis and biological evaluation of some stilbene derivatives
Several trans and cis stilbenes with substitution n the olefinic bridge were synthesized and characterized by IR, NMR and mass spectroscopy in an effort to obtain ubstances that could be more readily formulated. All the synthesized compounds were screened against Molt4/C8, CEM and L1210 cell lines. None of these compounds were ndowed with pronounced cytostatic activity. However,Schiff derivatives emerged as cytostatic agents (IC50: 0.77-10 μg/ml) that deserve further investigation. Springer Science+Business Media, LLC 2010.
Karki, Subhas Somalingappa,Bhutle, Santosh Ramarao,Sahoo, Subhas,Reddy, Ratnakar,Balzarini, Jan,De Clercq, Erik,Darji, Satyanarayana Y.
experimental part
p. 1349 - 1356
(2012/05/05)

NOVEL HISTONE DEACETYLASE INHIBITORS
Provided herein are novel, stilbene like compounds of the general formula (I), their derivatives, analogs, tautomeric forms, stereoisomers, polymorphs, hydrates, metabolites, prodrugs, solvates, pharmaceutically acceptable salts and compositions thereof. These compounds can inhibit HDACs and are useful as a therapeutic or ameliorating agent for diseases that are involved in cellular growth such as WO 2009/047615 A2 malignant tumors, autoimmune diseases, skin diseases, infections, inflammation, etc.
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Page/Page column 38

(2010/09/07)

Friedel-Crafts alkylation of benzene with 1,2-diphenyl-2-propanol, 1-chloro-2,3-diphenylpropane and 2-methyl-1-phenyl-2-butanol
The alkylation of benzene with 1,2-diphenyl-2-propanol (1) using AlCl 3/CH3NO2 catalyst gave a mixture of 1,2,2- (4) and 1,1,2-triphenylpropane (5) as product alkylates. With 85% H 2SO4 catalyst, the product consisted of E-1,2-diphenylpropene (6) after 2 h of a mixture of 5 and 6 after 18 h. Similar alkylation of benzene with 1-chloro-2,3-diphenylpropane (2) using AlCl 3 catalyst gave a mixture consisting of 4, 5 and 6. Finally, alkylation of benzene with 2-methyl-1-phenyl-2-butanol (3) using AlCl 3/CH3NO2 gave 2-methyl-1,1-diphenylbutane (10) as sole product alkylate. The identities of the products were confirmed spectroscopically and by comparison with unequivocally prepared samples. Mechanisms are proposed to rationalise the observed results.
Khalaf, Ali A.,Awad, Ibrahim M.,El-Emary,El-Aal, H.A.K. Abd
experimental part
p. 595 - 600
(2011/08/21)

NOVEL HISTONE DEACETYLASE INHIBITORS
Provided herein are novel, stilbene like compounds of the general formula (I), their derivatives, analogs, tautomeric forms, stereoisomers, polymorphs, hydrates, metabolites, prodrugs, solvates, pharmaceutically acceptable salts and compositions thereof. These compounds can inhibit HDACs and are useful as a therpeautic or ameliorating agent for diseases that are involved in cellular growth such as malignant tumors, autoimmune diseases, skin diseases, infections, inflammation, etc.
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Page/Page column 53

(2009/05/30)

NOVEL COMPOUNDS, ISOMER THEREOF, OR PHARMACEUTICALLY ACCEPTABLE SALTS THEREOF AS VANILLOID RECEPTOR ANTAGONIST; AND PHARMACEUTICAL COMPOSITIONS CONTAINING THE SAME
This present invention relates to novel compounds, isomer thereof or pharmaceutically acceptable salts thereof as vanilloid receptor (Vanilloid Receotor 1; VR1; TRPV1 )antagonist; and a pharmaceutical composition containing the same. The present invention provides a pharmaceutical composition for preventing or treating a disease such as pain, migraine, arthralgia, neuralgia, neuropathies, nerve injury, skin disorder, urinary bladder hypersensitiveness, irritable bowel syndrome, fecal urgency, a respiratory disorder, irritation of skin, eye or mucous membrane, stomach-duodenal ulcer, inflammatory diseases, ear disease, and heart disease.
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Page/Page column 156-157

(2008/06/13)

Cp2ZrCl2-mediated three-component coupling reactions of CO2, ethylene (or alkynes), and electrophiles leading to carboxylic acid derivatives
Zirconacycles 1 and 2 can be simply generated from Cp2ZrCl 2, EtMgBr, and an atmospheric pressure of CO2. The treatment of Cp2ZrCl2 with EtMgBr followed by exposure to CO2 generates zirconacycle 1, which can react with various electrophiles to give a variety of carboxylic acid derivatives. Unsaturated zirconacycles 2 can also generated from Cp2ZrCl2, EtMgBr, alkynes, and CO2. Complexes 2 react with electrophiles to give α,β-unsaturated acids stereoselectively.
Yamashita, Kohei,Chatani, Naoto
p. 919 - 922
(2007/10/03)

On the mechanism of a modified Perkin condensation leading to α-phenylcinnamic acid stereoisomers - Experiments and molecular modelling
A modified Perkin condensation leading to α-phenylcinnamic acid stereoisomers affords predominantly or exclusively the (E)-isomer. Reaction duration, temperature, and polarity of the solvent affect the isomeric distribution only to a minor extent. However, geometry optimization of the stereoisomers by semiempirical quantum chemical methods revealed that their thermodynamic stabilities in the absolute minimum are the same. (E)-(Z)-isomerization under the conditions of the Perkin condensation resulted in an equilibrium mixture of nearly 1:1 composition, thus corroborating the results of the computations. Comparing the detailed potential energy maps of the isomers obtained at the semiempirical level of theory may explain the controversy. The (Z)-isomer has a structured potential energy surface with few but well-defined minima, whereas that of the (E)-isomer shows an extended flat plateau enabling this isomer to approach a minimum (which is close to the global one) right after its formation.
Palinko, Istvan,Kukovecz, Akos,Toeroek, Bela,Koertvelyesi, Tamas
p. 1097 - 1104
(2007/10/03)

A non-cope among the cope rearrangements of 1,3,4,6-tetraphenylhexa-1,5- dienes
The set of 1,3,4,6-tetraphenylhexa-1,5-dienes (1) represents a perturbation of Cope's rearrangement by four radical-stabilizing phenyl groups all positioned to drive the transition region toward the homolytic- colligative end of the mechanistic spectrum. The appearance of (Z)-isomers being suppressed thermodynamically by a steric interaction of +2.6 kcal mol- 1 per cis double bond, an equilibration that is stereochemically not of any Cope type, emerges as the predominant reaction. It is an interconversion of rac-(E,E)-1 and meso-(E,E)-1 (48:52; 77.3-115.3 °C) with the following values of the enthalpy, entropy, and volume of activation: ΔH(+) = 30.7 ± 0.2 kcal mol-1, ΔS(+) = +2.1 ± 0.4 cal mol-1 K-1, and ΔV(+) = +13.5 ± 0.1 cm-3 mol-1, respectively. Structures have been established by X- ray crystallographic analysis; a possible relationship between dihedral angle and bond lengths in the styrene portions is proposed. The entropy of activation is incompatible with a chair or boat Cope rearrangement; the volume of activation is neither low enough for a pericyclic Cope ('concerted') mechanism nor high enough for a homolytic-colligative mechanism involving full dissociation as the rate-determining step. Trapping and a crossover experiment give some but only partial support to the intermediacy of free radicals. At higher temperatures, however, electron spin resonance experiments demonstrate an equilibrium with kinetically free (E,E)-1,3- diphenylallyl radicals. These observations are rationalized in terms of geometric reorganization within the confines of a 'cage'. Resolution by chiral chromatography of rac-(E,E)-1 allows recognition of a fast racemization (40-65 °C), of which ΔH(+) (21.3 ± 0.1 kcal mol-1), DS(+) (-13.2 ± 0.3 cal mol-1 K-1), and ΔV(+) (-7.4 ± 0.4 cm-3 mol-1) are consistent with a pericyclic Cope rearrangement. Enriched (Z)-isomers undergo Cope rearrangements in accord with the known influence of axiality and the chair/boat alternative on the energy of the transition region.
Doering,Birladeanu, Ludmila,Sarma, Keshab,Blaschke,Scheidemantel, Ursula,Boese,Benet-Bucholz, Jordi,Klaerner,Gehrke, Jan-Stephan,Zimny, Bernd Ulrich,Sustmann,Korth, Hans-Gert
p. 193 - 203
(2007/10/03)

Reactions of carbonyl compounds in basic solutions. Part 34. The mechanism of the base-catalysed ring fission of 2,3-diphenylcycloprop-2-en-1-one
The rate coefficients for the base-catalysed ring fission of a series of 2-phenyl-3-(2-, 3-or 4-substituted phenyllcycloprop-2-en-1-ones to give the corresponding (E)-2,3-diphenylacrylic acids have heen determined in water at 30.0 °C, as well as for the unsubstituted compound at 40.0, 50.0 and 60.0 °C. The effects of meta-and para-substituents on the rates have been correlated using the Hammett equation to give a reaction constant, p, equal to ca 1.2 at 30 °C. For the unsubstituted compound, the activation parameters have been calculated and the kinetic solvent isotope effect has been studied. The effects of ortho-substituents on the rates appear to be mainly polar, rather than steric, in origin. The evidence indicates a mechanistic pathway which proceeds by addition of hydroxide anion to the ketone, which is rate-determining. The adduct suffers ring fission to give the final product via a carbanionic intermediate.
Bowden, Keith,Burgess, Emma J.
p. 1594 - 1600
(2007/10/03)

New Convenient One-Pot Methods of Conversion of Alkynes to Cyclobutenediones or α,β-Unsaturated Carboxylic Acids Using Novel Reactive Iron Carbonyl Reagents
Reactions of NaHFe(CO)4/RX or [HFe3(CO)11]- reagents with alkynes lead to the formation of the corresponding α,β-unsaturated carboxylic acids and/or the cyclobutenediones. The reagent generated in situ using the NaHFe(CO)4/CH3I combination in THF, on reaction with alkynes followed by CuCl2·2H2O oxidation, gives the corresponding cyclobutenediones (27-42%) and α,β-unsaturated carboxylic acids (10-22%), whereas the reagent generated using CH2Cl2 in place of CH3I leads to α,β-unsaturated carboxylic acids (37-60%) and their derivatives (35-55%) at 25°C. The same reagent system in the presence of acetic acid (4 equiv) yields the corresponding cyclobutenedione (33%). The reaction using Me3SiCl gives the corresponding α,β-unsaturated carboxylic acids (45-54%) at 25°C and the corresponding cyclobutenediones (51-63%) at 60°C. Interestingly, the reaction of the [HFe3(CO)11]- species generated using Fe(CO)5/NaBH4/CH3COOH, with alkynes at 25°C, followed by CuCl2·2H2O oxidation gives the corresponding cyclobutenediones (60-73%). The possible intermediates and pathways for the formation of α,β-unsaturated carboxylic acids and cyclobutenediones are discussed.
Periasamy, Mariappan,Rameshkumar, Chellappan,Radhakrishnan, Ukkiramapandian,Brunet, Jean-Jacques
p. 4930 - 4935
(2007/10/03)

Protonation and ring closure of stereoisomeric α-substituted cinnamic acids in superacidic media studied by 13C NMR spectroscopy and computations
Five α-substituted cinnamic acids [(E)- and (Z)-2,3-diphenyl-, (E)- and (Z)-3-(2-methoxyphenyI)-2-phenyl- and (E)-2-(2-methoxyphenyl)-3-phenyl-propenoic acids] have been protonated in fluorosulfonic acid at -78°C. Protonation of the carboxylic group and a second protonation on the methoxy group at -78°C or the ring bearing the methoxy group at 0°C have been observed by 13C NMR spectroscopy. Upon protonation (Z)-α-phenylcinnamic acid is transformed to a protonated indenol derivative. Dehydrative ring closure begins at -78°C and goes to completion at 0°C. Similar transformations of the other studied Z-acid are suppressed by the deactivating effect of the protonated methoxy group. Only protonation has been observed for the E-acids at -78°C as well as 0°lculations at the HF/3-21G level provide the equilibrium structures of the corresponding cations. Results of IGLO/13C NMR shift calculations are in good agreement with the experimental findings.
Palinko, Istvan,Burrichter, Arwed,Rasul, Golam,Toeroek, Bela,Prakash, G. K. Surya,Olah, George A.
p. 379 - 385
(2007/10/03)

A new method for the regio and stereoselective hydrocarboxylation of alkynes using NaHFe(CO)4/CH2Cl2 system
The reagent generated in situ in THF using NaHFe(CO)4 and CH2Cl2 was used for the regio and stereoselective hydrocarboxylation of terminal and internal alkynes to obtain α,β-unsaturated carboxylic acid derivatives.
Periasamy, Mariappan,Radhakrishnan, Ukkiramapandian,Rameshkumar, Chellappan,Brunet, Jean-Jacques
p. 1623 - 1626
(2007/10/03)

Hydration of Alkynes by a PtCl4-CO Catalyst
Treatment of PtCl4 with CO at 40-110°C forms a powerful alkyne hydration catalyst that operates both under homogeneous conditions in wet THF and under phase-transfer conditions in (CHCl2)2/H2O in the presence of tricaprylmethylammonium chloride (Aliquat 336). Complex HPtCl(CO)2 is regarded as the active hydration catalyst. It is assumed to be formed by initial transformation of PtCl2 to H2[Pt3(CO)6]n (n = 5, 6) followed by reaction with HCl (generated by decomposition of the starting platinum salt).
Baidossi, Wa?l,Lahav, Michal,Blum, Jochanan
p. 669 - 672
(2007/10/03)

Effect of substituents on the 13C NMR chemical shifts of para-substituted α-phenyl-β-pyridylacrylic acids
The 13C NMR spectra of para-substituted α-phenylcinnamic and 3- and 4-pyridylacrylic acids, with a wide range of substituents effects, were determined in deuterated dimethylsulfoxide (DMSO-d6). The effect of substituents in both the α-phenyl and β-pyridine groups in these acids is investigated using linear free energy relationships and multiple regression analysis as applied to 13C NMR chemical shifts of the C(α) and C(β) of the ethylenic bond and the carboxylic group carbon. Dissection of the α-phenyl substituent effects into the inductive and resonance components, using the dual substituent parameter (DSP) method, points to a blend of inductive and resonance effects in the π-electronic system.
Jovanovi?,Mi?i?-Vukovi?,Drmani?,?anadi
p. 39 - 41
(2007/10/03)

Double carbonylation of alkynes using NaHFe(CO)4
The reagent generated in situ using NaHFe(CO)4 and MeI in THF, on reaction with alkynes followed by CuCl2 oxidation, gives the corresponding cyclobutenediones in moderate yields (27-42%) in addition to the corresponding α,β-unsaturated carboxylic acids (10-22%).
Periasamy, Mariappan,Radhakrishnan, Ukkiramapandian,Brunet, Jean-Jacques,Chauvin, Remi,El Zaizi, Abdel Wahed
p. 1499 - 1500
(2007/10/03)

Rearrangement reaction of α-phenylcinnamic acid trimethylsilyl esters upon electron impact ionization: Practical and theoretical aspects [2]
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Palinko,Horvath,Torok
p. 823 - 824
(2007/10/03)