cas 17041-46-2, ETHYL COUMARATE | Articles data

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One-pot cascade synthesis of 2,3-disubstituted 2,3-dihydrobenzofurans via ortho-quinone methide intermediates generated in situ
A simple and efficient one-pot cascade reaction for the regioselective synthesis of trans or cis/trans 2,3-disubstituted 2,3-dihydrobenzofurans is reported. The method involves fluoride-induced desilylation, generation of o-quinone methide (o-QM) by chloride or nitrate anion elimination, Michael addition and intramolecular 5-exo-tet elimination of a bromide anion. Nitrate, acetoxy and chloride anions are compared as leaving groups in the formation of the in situ generated o-QM.
Shaikh, Abdul Kadar,Varvounis, George
p. 14892 - 14896
(2015)
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Expeditious synthesis of bicyclic pyrrolidine/pyrrolizidine/thiazolidine grafted macrocycles through intramolecular 1,3-dipolar cycloaddition of azomethine ylides
Stereoselective synthesis of bicyclic pyrrolidine and pyrrolizidine grafted macrocycles has been accomplished through intramolecular 1,3-dipolar cycloaddition (1,3-DC) reaction. Alkenyl aldehydes 4a-b derived from salicylaldehyde have been reacted with se
Purushothaman,Prasanna,Raghunathan
p. 6450 - 6454
(2013)
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Coumarins by Direct Annulation: β-Borylacrylates as Ambiphilic C3-Synthons
Modular β-borylacrylates have been validated as programmable, ambiphilic C3-synthons in the cascade annulation of 2-halo-phenol derivatives to generate structurally and electronically diverse coumarins. Key to this [3+3] disconnection is the BPin unit which serves a dual purpose as both a traceless linker for C(sp2)–C(sp2) coupling, and as a chromophore extension to enable inversion of the alkene geometry via selective energy transfer catalysis. Mild isomerisation is a pre-condition to access 3-substituted coumarins and provides a handle for divergence. The method is showcased in the synthesis of representative natural products that contain this venerable chemotype. Facile entry into π-expanded estrone derivatives modified at the A-ring is disclosed to demonstrate the potential of the method in bioassay development or in drug repurposing.
Wienhold, Max,Molloy, John J.,Daniliuc, Constantin G.,Gilmour, Ryan
supporting information
p. 685 - 689
(2020/11/30)

Free radical scavenging and α-glucosidase inhibitory activity of (E)-methyl/ethyl-3-(2-hydroxyphenyl)acrylates
(E)-Methyl/ethyl-3-(2-hydroxyphenyl)acrylates 3a-x have been prepared by the reaction of salicylaldehydes 1a-l with Wittig reagents such as methyl (triphenylphosphoranylidene)acetate 2a and ethyl (triphenylphosphoranylidene)acetate 2b in dry DCM at room t
Harikrishna, G.,Hariprasad, K. Siva,Raju, B. China,Tiwari, A. K.,Zehra, A.
p. 111 - 116
(2021/09/28)

Visible-Light-Induced C(sp2)-C(sp3) Coupling Reaction for the Regioselective Synthesis of 3-Functionalized Coumarins
A photocatalysis strategy for the regioselective synthesis of 3-functionalized coumarins is reported. With visible light irradiation, a direct and regioselective C(sp2)-C(sp3) coupling reaction of 3-(2-hydroxyphenyl)acrylates with ethers or thioethers occurs by using Ru(bpy)3Cl2·6H2O as a photocatalyst and TBHP as an oxidant. The cascade process involves alkenylation of the C(sp3)-H bond of ethers and lactonization, furnishing 3-alkylated coumarins as the final products. This approach is characterized by a broad substrate scope, mild reaction conditions, and simplified operation. The synthesis of 3-alkylated coumarins could be realized by a one-pot procedure, starting from commercially available salicylaldehyde.
Li, Hanjie,Lin, Zhenwei,Lu, Ping,Qiao, Li,Wang, Yanguang,Xie, Jianwei,Zhang, Ke
supporting information
p. 9552 - 9562
(2021/07/26)

Platinum complex containing diphosphine meta-position carborane ligand and preparation method and application of platinum complex
The invention relates to a platinum complex containing a diphosphine m-carborane ligand and a preparation method and application of the platinum complex, the method of the platinum complex comprises the following steps: reacting n-BuLi with m-carborane m-
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Paragraph 0031; 0035-0038; 0053-0057

(2021/04/17)

Ruthenium-catalyzed intramolecular arene C(sp2)-H amidation for synthesis of 3,4-dihydroquinolin-2(1 H)-ones
We report the [Ru(p-cymene)(l-proline)Cl] ([Ru1])-catalyzed cyclization of 1,4,2-dioxazol-5-ones to form dihydroquinoline-2-ones in excellent yields with excellent regioselectivity via a formal intramolecular arene C(sp2)-H amidation. The reactions of the 2- and 4-substituted aryl dioxazolones proceeds initially through spirolactamization via electrophilic amidation at the arene site, which is para or ortho to the substituent. A Hammett correlation study showed that the spirolactamization is likely to occur by electrophilic nitrenoid attack at the arene, which is characterized by a negative ρ value of -0.73.
Au, Chi-Ming,Ling, Cho-Hon,Sun, Wenlong,Yu, Wing-Yiu
supporting information
p. 3310 - 3314
(2021/05/29)

Cascade Synthesis of 4-Arylcoumarins: Pd-Catalyzed Arylations and Cyclizations with (E)-Ethyl 3-(2-Hydroxyaryl)acrylates and Triarylantimony Difluorides
Herein, we describe a simple general method for the synthesis of 4-arylcoumarins using pentavalent organoantimony compounds. The reactions of 3-(2-hydroxyaryl)acrylates with triarylantimony difluorides in the presence of Pd(OAc)2 (10 mol-%) and 2,2'-bipyridyl (10 mol-%) at 80 °C under aerobic conditions afforded 4-arylcoumarins in good-to-excellent yields. This protocol involves a cascade oxidative Heck-type arylation followed by cyclization, with all the aryl groups in the triarylantimony difluoride transferred to the coupling products. Triarylantimony difluorides resulted in better outcomes than those obtained with other pentavalent organoantimony or bismuth compounds.
Kitamura, Yuki,Matsumura, Mio,Kato, Yukari,Murata, Yuki,Yasuike, Shuji
supporting information
p. 1652 - 1657
(2020/03/05)

Late-Stage Direct o-Alkenylation of Phenols by PdII-Catalyzed C?H Functionalization
o-Alkenylation of unprotected phenols has been developed by direct C?H functionalization catalyzed by PdII. This work features phenol group as a directing group and realizes highly site-selective C?H bond functionalization of phenols to achieve the corresponding products in moderate to excellent yields at 60 °C. The advantages of this reaction include unprecedented C?H functionalization using phenol as a directing group, high regioselectivity, good substrate scope, mild reaction conditions, and high efficiency. To the best of our knowledge, this is the first example of a regioselective C?H alkenylation of unprotected phenols utilizing phenolic hydroxyl group as a directing group. The alkenylation of unprotected tyrosine and intramolecular cyclization are also successfully carried out under this catalytic system in good yields. Furthermore, this novel method enables a late-stage modification of complex phenol-containing bioactive molecules toward a diversity-oriented drug discovery.
Dou, Yandong,Kenry,Liu, Jiang,Jiang, Jianze,Zhu, Qing
supporting information
p. 6896 - 6901
(2019/05/07)

Rh-Catalyzed Deformylative Coupling of Salicylaldehydes with Acrylates and Acrylamides
An unprecedented deformylative coupling of salicylaldehydes to acrylates and acrylamides under Rh-catalyzed conditions is reported. These deformylative couplings afforded o-hydroxycinnamates and o-hydroxycinnamamides with broad functional group tolerance and high chemoselectivity under milder reaction conditions.
Rao, Maddali L.N.,Ramakrishna, Boddu S.
supporting information
p. 5677 - 5683
(2019/05/01)

Phenol compound ortho-position direct olefination method and olefinated phenol compound
The invention relates to a phenol compound ortho-position direct olefination method and an olefinated phenol compound prepared with the method. The method comprises the steps that a phenol compound shown by the formula (II) and an olefin compound shown by
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Paragraph 0054; 0055; 0056; 0057

(2019/05/04)

Palladium catalyzed Heck-arylation/cyclization cascade: An environmentally benign and efficient synthesis of 4-arylcoumarins in water
An environmentally benign and efficient approach for the synthesis of 4-arylcoumarins from ortho-hydroxy cinnamate ester derivatives with aryl iodides was developed in water under aerobic conditions. This transformation proceeds through a palladium catalyzed Heck-arylation/cyclization cascade reaction. The present protocol features a wide substrate scope and readily available starting materials to afford the desired products in high to excellent yields.
Chen, Junmin,Liu, Wei,Zhou, Liandi,Zhao, Yongli
supporting information
p. 2526 - 2531
(2018/05/28)

Radical-induced expeditious stereoselective synthesis of 2-alkyl 3-allyl trans-2,3-dihydrobenzofurans (TADHBs)
A thorough study on radical-induced cyclopropyl ring fragmentation with encompassed olefinic and cyclopropane environment has been performed. Interestingly, the fragmentation has occasioned onto a stereoselective synthesis of 3-allyl trans-2,3-dihydrobenzofurans with impressive yields. The trans-dihydrobenzofurans are present as central core in many molecules of medicinal interest and the present protocol deliver a straight forward access to the embedded molecular architecture.
Sarkar, Debayan,Sahoo, Sushree Ranjan
p. 574 - 581
(2018/02/06)

3-Trifluoromethylated Coumarins and Carbostyrils by Radical Trifluoromethylation of ortho-Functionalized Cinnamic Esters
A method for the trifluoromethylation of ortho-hydroxycinnamic esters was developed to achieve the regioselective synthesis of 3-trifluoromethylated coumarins. The reaction was performed by using the Togni reagent as the CF3source under mild conditions and showed good functional- group tolerance. The scope of this copper-mediated method was further expanded to the synthesis of 3-trifluoromethylated carbostyrils starting from ortho-aminocinnamic derivatives. Interestingly, a sequential one-pot synthesis of 3-trifluoromethylated coumarins starting from salicylaldehydes was further developed. The mechanism of this cascade reaction was explored, and a radical pathway was found to be consistent with the obtained results.
Chaabouni, Slim,Simonet, Florent,Fran?ois, Alison,Abid, Souhir,Galaup, Chantal,Chassaing, Stefan
supporting information
p. 271 - 277
(2017/01/24)

S,O-Ligand-Promoted Palladium-Catalyzed C-H Functionalization Reactions of Nondirected Arenes
Pd(II)-catalyzed C-H functionalization of nondirected arenes has been realized using an inexpensive and easily accessible type of bidentate S,O-ligand. The catalytic system shows high efficiency in the C-H olefination reaction of electron-rich and electron-poor arenes. This methodology is operationally simple, scalable, and can be used in late-stage functionalization of complex molecules. The broad applicability of this catalyst has been showcased in other transformations such as Pd(II)-catalyzed C-H acetoxylation and allylation reactions.
Naksomboon, Kananat,Valderas, Carolina,Gómez-Martínez, Melania,álvarez-Casao, Yolanda,Fernández-Ibá?ez, M. ángeles
p. 6342 - 6346
(2017/09/15)

Bioactivity and structure-activity relationship of cinnamic acid esters and their derivatives as potential antifungal agents for plant protection
A series of cinnamic acid esters and their derivatives were synthesized and evaluated for antifungal activities in vitro against four plant pathogenic fungi by using the mycelium growth rate method. Structure-activity relationship was derived also. Almost all of the compounds showed some inhibition activity on each of the fungi at 0.5 mM. Eight compounds showed the higher average activity with average EC50 values of 17.4-28.6 μg/mL for the fungi than kresoxim-methyl, a commercial fungicide standard, and ten compounds were much more active than commercial fungicide standards carbendazim against P. grisea or kresoxim-methyl against both P. grisea and Valsa Mali. Compounds C1 and C2 showed the higher activity with average EC50 values of 17.4 and 18.5 μg/mL and great potential for development of new plant antifungal agents. The structure-activity relationship analysis showed that both the substitution pattern of the phenyl ring and the alkyl group in the alcohol moiety significantly influences the activity. There exists complexly comprehensive effect between the substituents on the phenyl ring and the alkyl group in the alcohol moiety on the activity. Thus, cinnamic acid esters showed great potential the development of new antifungal agents for plant protection due to high activity, natural compounds or natural compound framework, simple structure, easy preparation, low-cost and environmentally friendly.
Zhou, Kun,Chen, Dongdong,Li, Bin,Zhang, Bingyu,Miao, Fang,Zhou, Le
(2017/04/26)

Recycled Pd/C-Catalyzed Heck Reaction of 2-Iodoanilines under Ligand-Free Conditions
Recyclable Pd/C-catalyzed Heck reaction of 2-iodoanilines with acrylate has been developed. The reaction occurred readily in 1,4-dioxane using Pd/C (10 wt%) as catalyst under ligand-free conditions, and the cross-coupling products were obtained with medium to high yield. Gram-scale reactions and recycling of the catalyst were also demonstrated.
Zhou, Xiao-Yu,Chen, Xia,Wang, Liang-Guang
supporting information
p. 5364 - 5370
(2017/12/14)

Palladium catalyzed Heck reaction of 2-iodoanilines under ligand-free conditions in air
Palladium catalyzed Heck reaction of 2-iodoanilines and acrylate has been developed. The palladium catalyzed Heck reaction of 2-iodoanilines can readily occur in CH3CN using Pd(OAc)2 (5.0 mol%) as catalyst, NEt3 as base un
Chen, Xia,Zhou, Xiao-Yu,Wang, Liang-Guang
supporting information
p. 2096 - 2102
(2017/10/26)

Trans-cinnamic acid ester compound and its synthetic method and application
The invention relates to a trans cinnamic acid ester compound, as well as a synthetic method and application thereof. At present, a typic miticide has the growing problems, such as drug resistance and environment and ecology, so that a new animal miticide needs to be developed very urgently. The trans cinnamic acid ester compound has the molecular structure shown in the specification, wherein R refers to alkyl radical, R1 and R2 refer to hydrogen, hydroxide radical, alkyl radical, alkoxy, fatty acyloxy, halogen, methylenedioxy or nitro, and are the same or different; the trans cinnamic acid ester compound can be used for preparing miticides for animals and people. The compound serves as a novel miticide, is relatively low in toxicity, small in molecular weight, few in synthetic steps, simple to operate, low in production cost, and suitable for large-scale industrial production; the acaricidal activity is remarkably stronger that of a miticide applied in current all clinics.
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Paragraph 0033; 0034

(2016/10/07)

Palladium(II) oxide impregnated on magnetite as a catalyst for the synthesis of 4-arylcoumarins: Via a Heck-arylation/cyclization process
Heck-arylation/cyclization was achieved using heterogeneous palladium(ii) oxide impregnated on magnetite catalyst (2.5 mol%) with a lower catalyst loading than that reported for similar processes. Ethanol was used as a non-toxic and bio-renewable solvent. Good yields were afforded using a broad range of substrates (40-98%). The catalyst could be partially recycled, and analyses confirmed the almost total reduction of palladium(ii) oxide to palladium(0) as well as the iodine poissoning effect, which is the main barrier to complete recyclability.
Pérez, Juana M.,Cano, Rafael,McGlacken, Gerard P.,Ramón, Diego J.
p. 36932 - 36941
(2016/05/24)

One-Step Synthesis of Substituted Benzofurans from ortho- Alkenylphenols via Palladium-Catalyzed C=H Functionalization
A dehydrogenative oxygenation of C(sp2)=H bonds with intramolecular phenolic hydroxy groups has been developed, which provides a straightforward and concise access to structurally diversely benzofurans from ortho-alkenylphenols. The reaction is catalyzed by palladium on carbon (Pd/C) without any oxidants and sacrificing hydrogen acceptors.
Yang, Dejun,Zhu, Yifei,Yang, Na,Jiang, Qiangqiang,Liu, Renhua
supporting information
p. 1731 - 1735
(2016/06/09)

Ligand-Free Heck Reactions of Aryl Iodides: Significant Acceleration of the Rate through Visible Light Irradiation at Ambient Temperature
A mild Heck reaction of aryl iodides and olefins was realized by the cooperation of a palladium and a photoredox catalyst under the irradiation of visible light. This protocol works well to synthesize stilbenes with high Z/E ratios and (E)-cinnamates in the absence of ligands at ambient temperature. Control experiments revealed that palladium salt, visible light and photoredox catalyst were all crucial for the achievement of this cross-coupling under mild conditions. (Figure presented.).
Zhang, Heng,Huang, Xueliang
supporting information
p. 3736 - 3742
(2016/12/16)

Synthesis of the furo[2,3-b]chromene ring system of hyperaspindols a and B
The synthesis of the unique furo[2,3-b]chromene ring system found in hyperaspidinols A and B, acylphloroglucinols from Hypericum chinense has been achieved in twelve steps. By comparison of the NMR spectra of the synthesized compounds with those of the natural products, a relative stereochemistry is suggested, especially that of the ketal carbon.
Paterson, Danielle L.,Barker, David
supporting information
p. 265 - 270
(2015/04/14)

Ethyl cinnamate derivatives as promising high-efficient acaricides against Psoroptes cuniculi: Synthesis, bioactivity and structure-activity relationship
This paper reported the synthesis, structure-activity relationship (SAR) and acaricidal activity in vitro against Psoroptes cuniculi, a mange mite, of 25 ethyl cinnamate derivatives. All target compounds were synthesized and elucidated by means of MS, 1H- and 13C-NMR analysis. The results showed that 24 out of 25 tested compounds at 1.0 mg/mL demonstrated acaricidal activity in varying degrees. Among them, 6, 15, 26, 27 and 30 showed significant activity with median lethal concentration values (LC50) of 89.3, 119.0, 39.2, 29.8 and 41.2 μg/mL, respectively, which were 2.1- to 8.3-fold the activity of ivermectin (LC50=247.4 μg/mL), a standard drug in the treatment of Psoroptes cuniculi. Compared with ivermectin, with a median lethal time value (LT50) of 8.9 h, 27 and 30 showed smaller LTM50 values of 7.9 and 1.3 h, respectively, whereas 6, 15 and 26 showed slightly larger LT50 values of 10.6, 11.0 and 10.4 h at 4.5 μmol/mL. SARs showed that the presence of o-NO2 or m-NO2 on the benzene ring significantly improved the activity, whereas the introduction of a hydroxy, methoxy, acetoxy, methylenedioxy, bromo or chloro group reduced the activity. (E)-Cinnamates were more effective than their (Z)-isomer. Nevertheless, the carbon-carbon double bond in the acrylic ester moiety was proven not to be essential to improve the activity of cinnamic acid esters. Thus, the results strongly indicate that cinnamate derivatives, especially their dihydro derivatives, should be promising candidates or lead compounds for the development of novel acaricides for the effective control of animal or human acariasis.
Zhang, Bingyu,Lv, Chao,Li, Weibo,Cui, Zhiming,Chen, Dongdong,Cao, Fangjun,Miao, Fang,Zhou, Le
p. 255 - 262
(2015/04/22)

Facile synthesis of Z -alkenes via uphill catalysis
Catalytic access to thermodynamically less stable Z-alkenes has recently received considerable attention. These approaches have relied upon kinetic control of the reaction to arrive at the thermodynamically less stable geometrical isomer. Herein, we present an orthogonal approach which proceeds via photochemically catalyzed isomerization of the thermodynamic E-alkene to the less stable Z-isomer which occurs via a photochemical pumping mechanism. We consider two potential mechanisms. Importantly, the reaction conditions are mild, tolerant, and operationally simple and will be easily implemented.
Singh, Kamaljeet,Staig, Shannon J.,Weaver, Jimmie D.
supporting information
p. 5275 - 5278
(2014/05/06)

A straight forward synthesis of 4-aryl substituted 2-quinolones via Heck reaction
A variety of aryl halides have been successfully coupled with different olefins via Heck reaction in the presence of an active stimulant (Pd-NHC). An efficient one pot protocol for the easy access of structurally diverse 4-aryl-2-quinolones via domino Heck/cyclization reaction has been developed. This journal is
Gupta, Sumanta,Ganguly, Bhaskar,Das, Sajal
p. 41148 - 41151
(2015/02/05)

Palladium chloride catalyzed photochemical Heck reaction
PdCl2 catalyzed carbon-carbon bond formation (Heck reaction) between substituted aryl halides and olefins was carried out without a ligand, under irradiation with UV-visible light. The results demonstrated that UV-visible light accelerated the rate of the reaction, leading to an excellent yield of corresponding products. The recovered palladium nanoparticles could be thermally recycled several times. PdCl2 gave excellent conversion up to the fifth addition of substrate.
Waghmode, Suresh B.,Arbuj, Sudhir S.,Wani, Bina N.,Gopinath
supporting information
p. 348 - 351
(2013/06/04)

Ortho-dearomatization of phenols creating all-carbon spiro-bicycles
A range of alkene-linked phenols are generally and reliably dearomatized specifically at their ortho-positions to create all-carbon quaternary stereogenic centers at the corresponding spiro-ring junctions, thus establishing a viable solution to the long-standing synthetic challenge.
Zheng, Chao,Wang, Lu,Li, Jingjie,Wang, Leifeng,Wang, David Zhigang
supporting information
p. 4046 - 4049
(2013/09/12)

Pd(II)-catalyzed ortho - Or meta-C-H olefination of phenol derivatives
A combination of weakly coordinating auxiliaries and ligand acceleration allows for the development of both ortho- and meta-selective C-H olefination of phenol derivatives. These reactions demonstrate the feasibility of directing C-H functionalizations when functional groups are distal to target C-H bonds. The meta-C-H functionalization of electron-rich phenol derivatives is unprecedented and orthogonal to previous electrophilic substitution of phenols in terms of regioselectivity. These methods are also applied to functionalize α-phenoxyacetic acids, a fibrate class of drug scaffolds.
Dai, Hui-Xiong,Li, Gang,Zhang, Xing-Guo,Stepan, Antonia F.,Yu, Jin-Quan
supporting information
p. 7567 - 7571
(2013/06/27)

Heterogeneous photocatalysed Heck reaction over PdCl2/TiO 2
The heterogeneous PdCl2/TiO2 efficiently catalyzes the C-C bond formation (Heck reaction) between aryliodides and olefins under photochemical and mild reaction conditions. This process gives good to excellent conversion under optimized reaction conditions. After completion of the reaction, Pd2+ is reduced to Pd0. Further, Pd0 can be easily converted into Pd2+ by heating with ammonium chloride at 400°C for 30 min and the regenerated catalyst could be reused up to the third recycle with good catalytic activity. The catalysts (before and after reaction, as well as regenerated) were systematically characterized using Transmission Electron Microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, temperature programmed reduction and DRUV-visible spectroscopy techniques.
Waghmode, Suresh B.,Arbuj, Sudhir S.,Wani, Bina N.
p. 2911 - 2916
(2013/09/12)

Mizoroki-Heck reactions catalyzed by dichloro{bis[1- (dicyclohexylphosphanyl)piperidine]}palladium: Palladium nanoparticle formation promoted by (water-induced) ligand degradation
The palladium-based dichlorobis[1-(dicyclohexylphosphanyl)piperidine] complex - [(P{(NC5H10)(C6H11) 2})2Pd(Cl)2] is readily prepared in quantitative yield from the reaction of [Pd(cod)(Cl)2] (cod=cycloocta-1,5-diene) with two equivalents of 1-(dicyclohexylphosphanyl) piperidine in toluene under N2 within only a few minutes at room temperature. This complex is a highly active Heck catalyst with excellent functional group tolerance, which reliably operates at low catalyst loadings. Various activated, non-activated, deactivated, functionalized, sterically hindered, and heterocyclic aryl bromides, which may contain nitro, chloro or trifluoromethane groups, nitriles, acetales, ketones, aldehydes, ethers, esters, lactones, amides, anilines, phenols, alcohols, carboxylic acids, and heterocyclic aryl bromides, such as pyridines and derivatives, as well as thiophenes and aryl bromides containing methylsulfanyl groups have been successfully coupled with various (also functionalized) alkenes in excellent yields and selectivities (the E-isomers are typically exclusively formed) at 140 °C in the presence of 0.05 mol % of the catalyst in DMF. Even though lower catalyst loadings could be used for many electronically activated, non-activated and some electronically deactivated aryl bromides without noticeable loss of activity, the great advantage of the reaction protocol presented here lies in its reliability and general applicability, which allows its direct adoption to other aryl bromides without the neccessity of its modification. Experimental observations indicated that palladium nanoparticles are the catalytically active form. Consequently, whereas comparable levels of activity were observed for dichloro-bis(aminophosphine) complexes of palladium, a dramatic drop in activity was found for their phosphine-based analogue [(P(C6H 11)3)2Pd(Cl)2]. Copyright
Oberholzer, Miriam,Gerber, Roman,Frech, Christian M.
supporting information; experimental part
p. 627 - 641
(2012/04/23)

Coumarins from free ortho -hydroxy cinnamates by Heck-Matsuda arylations: A scalable total synthesis of (R)-tolterodine
Free ortho-hydroxy cinnamate ester derivatives are evaluated in the synthesis of structurally diverse 4-aryl-coumarins via a tandem Heck-Matsuda cyclization reaction. Free phenolic groups were considered incompatible with such a reaction, which usually provide the corresponding diazo dyes. A concise and scalable route employing a ligand-free, Pd-catalyzed Heck-Matsuda arylation under aerobic conditions for the preparation of (R)-Tolterodine in high overall yield and ee is also presented.
Barancelli, Daniela A.,Salles, Airton G.,Taylor, Jason G.,Correia, Carlos Roque D.
supporting information
p. 6036 - 6039
(2013/02/23)

One-pot synthesis of α,β-unsaturated esters promoted by sodium hydride
A new protocol for the synthesis of α,β-unsaturated esters was described with various aldehydes and ethyl acetate in presence of sodium hydride. Advantage of this method is high efficiency, shorter time period and inexpensive.
Swetha,Venkata Ramana,Shirodkar
experimental part
p. 522 - 524
(2011/12/15)

Site-directed anchoring of an N-heterocyclic carbene on a dimetal platform: Evaluation of a pair of diruthenium(i) catalysts for carbene-transfer reactions from ethyl diazoacetate
Site-directed anchoring of naphthyridine-functionalized N-heterocylic carbene (NHC) is achieved on a metal-metal singly bonded diruthenium(I) platform. Room-temperature treatment of 1-isopropyl-3-(5,7-dimethyl-1,8- naphthyrid-2-yl)imidazolium bromide (PINA·HBr) with Ru 2(CH3COO)2(CO)4 in acetonitrile affords the unsupported compound Ru2(CO) 4(μ2C2,N1-PIN)2Br 2 (1). Judicious alteration in the NHC ligand resulted in the bridged compound Ru2(CO)4(CH3COO)(μ2- μ2C2,N1-BIN)Br (2) (BIN = 1-benzyl-3-(3-phenyl-1,8-naphthyrid-2-yl)imidazol-2-ylidene). X-ray analysis revealed the chelate binding of PIN on each ruthenium at equatorial sites for 1, and the bridge-chelate binding of BIN spanning the diruthenium core for 2. The catalytic utilities of the BArF (tetrakis(3,5-bis(trifluoromethyl) phenyl)borate) salts of these compounds are evaluated toward carbene-transfer reactions from ethyl diazoacetate including aldehyde olefination, cyclopropanation, and X-H (X = O, N) insertions. 1-BArF is clearly shown to be the superior catalyst. DFT calculations are undertaken to understand the influence of NHC binding on the electronic structures of the "Ru 2(CO)4" core and to rationalize the lower activity of 2-BArF.
Saha, Biswajit,Ghatak, Tapas,Sinha, Arup,Rahaman, S. M. Wahidur,Bera, Jitendra K.
scheme or table
p. 2051 - 2058
(2011/06/18)

A RuII-N-heterocyclic carbene (NHC) complex from metal-metal singly bonded diruthenium(I) precursor: Synthesis, structure and catalytic evaluation
A mononuclear Ru(II)-N-heterocyclic carbene (NHC) complex [Ru II(CO)2(κ2C,N-BIN)(H2O)Br] [OTf] (OTf = trifluoromethane sulphonate) (1) has been synthesized in high-yield by the oxidative cleavage of the metal-metal singly-bonded diruthenium(I) precursor [Ru2(CO)4(CH3CN)6(OTf) 2] with 1,8-naphthyridine functionalized NHC precursor 1-benzyl-3-(5,7-dimethyl-1,8-naphthyrid-2-yl)imidazolium bromide (BIN·HBr) at room temperature. Compound 1 catalyzes transfer hydrogenation of ketones to alcohols, and carbene-transfer from ethyl diazoacetate to a variety of substrates. It is shown to be an excellent catalyst for the insertion of carbene into the O-H and N-H bonds of alcohols and amines.
Sinha, Arup,Daw, Prosenjit,Rahaman, S.M. Wahidur,Saha, Biswajit,Bera, Jitendra K.
experimental part
p. 1248 - 1257
(2011/04/22)

Ligustrazine derivatives. Part 5: Design, synthesis and biological evaluation of novel ligustrazinyloxy-cinnamic acid derivatives as potent cardiovascular agents
A series of novel ligustrazinyloxy-cinnamic acid derivatives were designed, synthesized and evaluated for their inhibitory effect on adenosine diphosphate (ADP)-induced platelet aggregation in vitro, and also assayed for their protective effect against hydrogen peroxide (H2O2)-induced oxidative damage on ECV-304 cells. Some compounds exhibited high activity in one or both of the assays, of which, compound 2e displayed the highest protective effect on the proliferation of the damaged ECV-304 cells (EC 50 = 0.020 mM), and compound 2f was the most active anti-platelet aggregation agent (EC50 = 0.054 mM). Structure-activity relationships were briefly discussed.
Chen, Hongfei,Li, Guoning,Zhan, Peng,Liu, Xinyong
experimental part
p. 5609 - 5615
(2012/01/03)

An efficient synthesis of 4-arylquinolin-2(1 H)-ones and 3-alkenyl-4-arylquinolin-2(1 H)-one using a Pd/NiFe2O 4-catalyzed consecutive Heck reaction
A convenient one-pot method for the synthesis of 4-arylquinolin-2(1H)-ones and 4-arylcoumarins has been described. The successive Heck reaction on substituted 2-iodoaniline and 2-iodophenol catalyzed by a Pd/nickel ferrite catalyst followed by in situ cyc
Borhade, Sanjay R.,Waghmode, Suresh B.
experimental part
p. 1355 - 1363
(2011/12/13)

Bimetallic catalysis involving dipalladium(I) and diruthenium(I) complexes
Dipalladium(I) and diruthenium(I) compounds bridged by two [{(5,7-dimethyl-1,8-naphthyridin-2-yl)amino}carbonyl]ferrocene (L) ligands have been synthesized. The X-ray structures of [Pd2L2][BF 4]2 (1) and [Ru2L2(CO) 4][BF4]2 (2) reveal dinuclear structures with short metal-metal distances. In both of these structures, naphthyridine bridges the dimetal unit, and the site trans to the metal-metal bond is occupied by weakly coordinating oxygen from the amido fragment. The catalytic utilities of these bimetallic compounds are evaluated. Compound 1 is an excellent catalyst for phosphine-free, Suzuki cross-coupling reactions of aryl bromides with arylboronic acids and provides high yields in short reaction times. Compound 1 is also found to be catalytically active for aryl chlorides, although the corresponding yields are lower. A bimetallic mechanism is proposed, which involves the oxidative addition of aryl bromide across the Pdi￡ Pd bond and the bimetallic reductive elimination of the product. Compound 1 is also an efficient catalyst for the Heck cross-coupling of aryl bromides with styrenes. The mechanism for aldehyde olefination with ethyl diazoacetate (EDA) and PPh3, catalyzed by 2, has been fully elucidated. It is demonstrated that 2 catalyzes the formation of phosphorane utilizing EDA and PPh3, which subsequently reacts with aldehyde to produce a new olefin and phosphine oxide. The efficacy of bimetallic complexes in catalytic organic transformations is illustrated in this work. Good couple: Metal-metal singly bonded [PdIi￡PdI] and [RuIi￡RuI] complexes exhibit bimetallic synergy in the catalytic Ci￡C bond-coupling and aldehyde-olefination reactions, respectively (see figure). Copyright
Das, Raj K.,Saha, Biswajit,Rahaman, S. M. Wahidur,Bera, Jitendra K.
scheme or table
p. 14459 - 14468
(2011/03/19)

Rhodium-catalyzed domino conjugate addition-cyclization reactions for the synthesis of a variety of N- and O-heterocycles: Arylboroxines as effective carbon nucleophiles
Facile and efficient Rh(I)-catalyzed domino conjugate addition-cyclization reactions of olefins bearing two electrophilic sites and a pendant nucleophile with organoboroxines have been developed to afford a variety of N- and O-heterocycles, such as 3,4-dihydroquinolin-2(1H)-ones, 3,4-dihydrocoumarins, and pyrrolidin-2-ones, which constitute important motifs in biologically active natural and synthetic organic compounds.
Park, Ja Ock,Youn, So Won
supporting information; experimental part
p. 2258 - 2261
(2010/07/17)

Enantioselective synthesis of functionalized 1-benzoxepines by phenoxide ion mediated 7-endo-tet carbocyclization of cyclic sulfates
A new asymmetric synthesis of 2,3-disubstituted 1-benzoxepines is described. Key steps include Sharpless asymmetric dihydroxylation of trans-α,β-unsaturated esters and phenoxide ion mediated intramolecular 7-endo-tet carbocyclization of syn-2,3-dihydroxy ester derived cyclic sulfates. Wiley-VCH Verlag GmbH & Co. KGaA, 2009.
Das, Sajal Kumar,Dinda, Subal Kumar,Panda, Gautam
scheme or table
p. 204 - 207
(2009/06/21)

Phosphine-free Pd-salen complexes as efficient and inexpensive catalysts for Heck and Suzuki reactions under aerobic conditions
Phosphine-free palladium-salen complexes, N,N′-bis(salicylidene)-ethylenediamino-palladium and N,N′-bis(salicylidene)-1,2-phenylenediamino palladium, are found to be highly active catalysts for the Heck olefination of aryl iodides and Suzuki reaction of aryl iodides and bromides giving excellent yields (70-90%) of products under aerobic conditions, in short reaction times (10-60 min).
Borhade, Sanjay R.,Waghmode, Suresh B.
p. 3423 - 3429
(2008/09/21)

Heck reaction over palladium supported on nickel ferrite as an efficient and inexpensive catalyst
The palladium supported on nickel ferrite found to be highly active catalyst for the Heck olefination of aryl iodides and activated aryl bromides providing an excellent yield in an aerobic condition, in shorter reaction time.
Borhade, Sanjay R.,Waghmode, Suresh B.
experimental part
p. 1549 - 1554
(2009/04/07)

Phosphine-catalyzed synthesis of highly functionalized coumarins
2-Styrenyl allenoates are converted into cyclopentene-fused dihydrocoumarins through phosphine-catalyzed regio- and diastereoselective [3 + 2] cycloadditions. Remarkably, changing the solvent from THF to benzene promotes the conversion of the 2-(2-nitrostyrenyl) allenoate into a tricyclic nitronate through a previously undocumented mode of phosphine catalysis. This nitronate was subjected to efficient face-, regio-, and exo-selective 1,3-dipolar cycloadditions to provide tetracyclic coumarin derivatives.
Henry, Christopher E.,Kwon, Ohyun
p. 3069 - 3072
(2008/02/11)

One-pot Wittig reactions in aqueous media: A rapid and environmentally benign synthesis of α,β-unsaturated carboxylic esters and nitriles
One-pot Wittig reactions of ethyl bromoacetate and bromoacetonitrile with aldehydes in the presence of PPh3 and LiOH in water were investigated. Most of the olefination reactions completed within 5-120 min in refluxing water containing 1.2 M LiCl to afford the olefin products in 71-97% yields with 100:0-55:45 ratios of E:Z isomers. Copyright Taylor & Francis Group, LLC.
Wu, Jinlong,Yue, Congyong
p. 2939 - 2947
(2007/10/03)

StePHOX, a new family of optically active, tunable phosphine-oxazoline ligands: syntheses and applications
A new class of optically active phosphine-oxazoline ligands has been synthesized wherein backbone chirality of these new ligands is installed by a Sharpless asymmetric dihydroxylation. Different backbone protecting groups as well as different substitution patterns on the oxazoline ring were studied. These ligands were tested in allylic substitution (with ee's up to 97%) and asymmetric Tsuji allylation.
Trudeau, Stéphane,Morken, James P.
p. 11470 - 11476
(2007/10/03)

Solvent-free Wittig olefination with stabilized phosphoranes - Scope and limitations
Neat mixtures of arene/hetarenecarbaldehydes, alkanals as well as alkenals with alkyl (triphenylphosphoranylidene)acetates react exothermally to furnish the corresponding alkenes. In certain cases, heating has to be provided externally. Reaction times are short and yields are generally very high. Neat mixtures of ketones and alkyl (triphenylphosphoranylidene)acetates react preferentially under microwave irradiation. The better stabilized phosphoranes do not react in the solid state with aldehydes or ketones under conventional heating, but necessitate microwave irradiation, although not all of the phosphoranes have been found to be stable under microwave irradiation at 500 W (2450 MHz).
Thiemann, Thies,Watanabe, Masataka,Tanaka, Yasuko,Mataka, Shuntaro
p. 578 - 584
(2007/10/03)

Convenient synthesis of a simple coumarin from salicylaldehyde and wittig reagent. IV: Improved synthetic method of substituted coumarins
The reaction of salicylaldehydes (2) with Horner-Wadsworth-Emmons (HWE) or Ando-HWE reagents was attempted to afford intramolecular phosphonate derivatives (6). A new synthetic method for coumarins (1) was achieved by using protected 2.
Takeuchi, Yasuo,Ueda, Norihiro,Uesugi, Koji,Abe, Hitoshi,Nishioka, Hiromi,Harayama, Takashi
p. 217 - 224
(2007/10/03)

Condensation of orthoacetates with aldehydes: A new strategy for the preparation of α,β-unsaturated esters
α,β-Unsaturated esters are formed in good yields when aldehydes are heated with orthoacetates in the presence of a catalytic amount of phenol.
Sampath Kumar,Rao, M. Shesha,Joyasawal, Sipak,Yadav
p. 4287 - 4289
(2007/10/03)

Microwave-induced in situ Wittig reaction of salicylaldehydes with ethyl chloroacetate and triphenylphosphine in solventless system
A variety of coumarins was prepared by an in situ Wittig reaction of salicylaldehydes, triphenylphosphine and ethyl chloroacetate using sodium methoxide/molecular sieves (3A) under solvent-free conditions.
Valizadeh,Shockravi,Heravi,Ghadim, H. Abbasi
p. 718 - 720
(2007/10/03)

An efficient route from coumarins to highly functionalized N-phenyl-2-quinolinones via Buchwald-Hartwig amination
Multiple substituted N-phenyl-2-quinolinones were obtained in a convenient four-step route from a variety of commercially available coumarins, utilizing customised Buchwald-Hartwig amination protocols for the key reaction. Whereas simple aminolysis of cou
Ullrich, Thomas,Giraud, Francis
p. 4207 - 4211
(2007/10/03)