- Heteroleptic copper(I) complexes as energy transfer photocatalysts for the intermolecular [2 + 2] photodimerization of chalcones, cinnamates and cinnamamides
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The [2 + 2] photodimerization of chalcones, cinnamates and cinnamamides can be effectively catalyzed by heteroleptic copper(I) complexes. The reactions were carried out under mild reaction conditions and the products were obtained in 20–72% yield under visible light irradiation. The copper-based photocatalyst comprised of the rigid phenanthroline ligand with substituents at the 2,9-positions and the 4,7-positions showed high activity in the photodimerization via an energy transfer pathway.
- Wu, Qing-An,Ren, Chen-Chao,Chen, Feng,Wang, Tian-Qi,Zhang, Yu,Liu, Xue-Fen,Chen, Jian-Bin,Luo, Shu-Ping
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supporting information
(2021/05/10)
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- Microwave accelerated the solvent-free synthesis of 4-aryl-3,4-dihydrocoumarin via the tandem reaction of cinnamic acids with phenols catalyzed by Amberlyst 15 resin
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Amberlyst 15 resin supported the tandem reaction of cinnamic acids with phenols under solvent-free reaction condition has been introduced to afford 4-aryl-3,4-dihydrocoumarin (neoflavanone) derivatives. The efficiency of solid acidic sulfonic resin (A-15) has been illustrated in two reaction activation methods such as microwave irradiation and conventional heating. The important roles of Amberlyst 15 have been emphasized strongly through the high yields of 4-aryl-3,4-dihydrocoumarin in the shorter time under the assistance of microwave irradiation than of conventional heating, and its high recovery and reusability for six catalyst runs. The original catalyst as well as the recycled catalyst were characterized by XRD and FE-SEM to study the correlation of the surface of reused catalyst and its recyclability.
- Le, Huu-Phuoc,Duong, Cong-Thang,Nguyen, Xuan-Triet,Luu, Thi Xuan Thi
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p. 2187 - 2203
(2021/07/02)
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- Site-Selective Acceptorless Dehydrogenation of Aliphatics Enabled by Organophotoredox/Cobalt Dual Catalysis
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The value of catalytic dehydrogenation of aliphatics (CDA) in organic synthesis has remained largely underexplored. Known homogeneous CDA systems often require the use of sacrificial hydrogen acceptors (or oxidants), precious metal catalysts, and harsh reaction conditions, thus limiting most existing methods to dehydrogenation of non- or low-functionalized alkanes. Here we describe a visible-light-driven, dual-catalyst system consisting of inexpensive organophotoredox and base-metal catalysts for room-temperature, acceptorless-CDA (Al-CDA). Initiated by photoexited 2-chloroanthraquinone, the process involves H atom transfer (HAT) of aliphatics to form alkyl radicals, which then react with cobaloxime to produce olefins and H2. This operationally simple method enables direct dehydrogenation of readily available chemical feedstocks to diversely functionalized olefins. For example, we demonstrate, for the first time, the oxidant-free desaturation of thioethers and amides to alkenyl sulfides and enamides, respectively. Moreover, the system's exceptional site selectivity and functional group tolerance are illustrated by late-stage dehydrogenation and synthesis of 14 biologically relevant molecules and pharmaceutical ingredients. Mechanistic studies have revealed a dual HAT process and provided insights into the origin of reactivity and site selectivity.
- Zhou, Min-Jie,Zhang, Lei,Liu, Guixia,Xu, Chen,Huang, Zheng
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supporting information
p. 16470 - 16485
(2021/10/20)
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- Hypervalent iodine(iii) induced oxidative olefination of benzylamines using Wittig reagents
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We have developed hypervalent iodine(iii) induced oxidative olefination of primary and secondary benzylamines using 2C-Wittig reagents, which provides easy access to α,β-unsaturated esters. Mild reaction conditions, good to excellent yields with high (E) selectivity, and a broad substrate scope are the key features of this reaction. We have successfully carried out the gram-scale synthesis of α,β-unsaturated esters.
- Ramavath, Vijayalakshmi,Rupanawar, Bapurao D.,More, Satish G.,Bansode, Ajay H.,Suryavanshi, Gurunath
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p. 8806 - 8813
(2021/05/26)
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- Photoinduced Oxidative Alkoxycarbonylation of Alkenes with Alkyl Formates
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A photoinduced oxidative alkoxycarbonylation of alkenes initiated by intermolecular addition of alkoxycarbonyl radicals has been demonstrated. Employing alkyl formates as alkoxycarbonyl radical sources, a range of α,β-unsaturated esters were obtained with good regioselectivity and E selectivity under ambient conditions.
- Tang, Wan-Ying,Chen, Ling,Zheng, Ming,Zhan, Le-Wu,Hou, Jing,Li, Bin-Dong
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supporting information
p. 3939 - 3943
(2021/05/26)
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- Mizoroki-Heck Reaction of Unstrained Aryl Ketones via Ligand-Promoted C-C Bond Olefination
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Mizoroki-Heck reaction of unstrained aryl ketone with acrylate/styrene is accomplished via palladium-catalyzed ligand-promoted C-C bond cleavage. Various (hetero)aryl ketones are compatible in the reaction, affording the alkene product in good to excellent yields. Further applications in the late-stage olefination of some drugs, natural products, and fragrance-derived aryl ketones demonstrate the synthetic utility of this protocol. By employing ketone as both the directing group and the leaving group, 1,2-bifunctionalization is achieved via sequential ortho-C-H alkylation/ipso-Heck olefination.
- Wang, Mei-Ling,Xu, Hui,Li, Han-Yuan,Ma, Biao,Wang, Zhen-Yu,Wang, Xing,Dai, Hui-Xiong
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p. 2147 - 2152
(2021/04/05)
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- Enantioselective Synthesis of 3,4-Dihydropyran-2-ones via Phase-Transfer-Catalyzed Addition-Cyclization of Acetylacetone to Cinnamic Thioesters
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Herein, we present the first example of synthesis of 3,4-dihydropyran-2-ones from cinnamic thioesters via a stereoselective phase-transfer-catalyzed domino Michael-cyclization reaction with acetylacetone. The reaction proceeded under the catalysis of Cinchona-derived quaternary ammonium phenoxide that, in combination with inorganic bases, provided 3,4-dihydropyran-2-ones in yields of up to 93% and enantioselectivities of up to 88% enantiomeric excess.
- Destro, Dario,Bottinelli, Carlo,Ferrari, Ludovica,Albanese, Domenico C. M.,Bencivenni, Grazia,Gillick-Healy, Malachi W.,Kelly, Brian G.,Adamo, Mauro F. A.
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supporting information
p. 5183 - 5192
(2020/04/10)
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- Donor-acceptor fluorophores as efficient energy transfer photocatalysts for [2 + 2] photodimerization
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Mild [2 + 2] photodimerization of enone substrates was induced by donor-acceptor fluorophores. Enone substrates were activated efficiently for anti-head to head dimerizations with a high yield (up to 83%) and high selectivity. The adjustable excited state potential also allows donor-acceptor fluorophores to be used for isomerization of the above substrates, confirming the potential of donor-acceptor fluorophores as energy transfer photocatalysts.
- Chen, Feng,Chen, Hao,Liu, Xue-Fen,Luo, Shu-Ping,Ren, Chen-Chao,Wu, Qing-An,Xu, Liang-Xuan,Yu, Xiao-Cong
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p. 3707 - 3716
(2020/06/03)
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- Preparation method of cinnamate compound
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The invention discloses a preparation method of a cinnamate compound, which comprises the following steps: sequentially adding a diaryl trifluoromethane sulfonic acid iodine compound, an acrylate compound, a palladium complex, an additive and a solvent into a reaction flask, reacting, and stirring at 70-90 DEG C for 15-20 hours; quenching and extracting; drying the extract, filtering, concentrating, and carrying out column chromatography purification to obtain the cinnamate compound. The problems that a traditional reaction catalyst is large in dosage and too high in reaction temperature are effectively solved, the performance of the palladium catalyst can be brought into full play, the palladium catalyst can rapidly conduct coordination reaction on electron-deficient olefin, the use efficiency of the catalyst is improved, the reaction temperature is reduced, a special reaction environment is not needed, raw materials are simple and easy to obtain, and reaction conditions are loose. The preparation method is a low-cost preparation method of the cinnamate compound.
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Paragraph 0028-0029
(2021/01/15)
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- Palladium Ion Catalysed Oxidative C–C Bond Formation Reactions in Arylboronic Acid: Application of Cordierite Monolith Coated Catalyst
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Abstract: Catalytic efficiency of palladium ion substituted in TiO2, Ti0.97Pd0.03O1.97 is successfully exploited for the oxidative homocoupling of arylboronic acid and oxidative Heck coupling reactions between arylboronic acid and olefins. The reaction protocol provides direct approach to synthesize biphenyls and cinnamates from moderate to good yield with good functional group tolerance. As a result, 11 symmetrical biaryls and 14 cinnamates were synthesized from readily available arylboronic acids. Ti0.97Pd0.03O1.97 powder catalyst is synthesized by solution combustion method and characterized by powder X-ray diffraction. The C–C bond formation reactions were carried out by catalyst cartridge method using Ti0.97Pd0.03O1.97 catalyst coated cordierite monolith. Coating of the catalyst on a cordierite monolith enhanced the applicability of the catalyst and made handling and recycling of the catalyst very easy. Catalyst was recovered and recycled for eight times in both homocoupling and oxidative Heck coupling reactions. The turnover number for both the reactions found to be 443 and 424, respectively. Graphic Abstract: [Figure not available: see fulltext.].
- Bhat, Shrikanth K.,Prasanna,Dasappa, Jagadeesh Prasad,Hegde
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p. 2911 - 2927
(2020/03/31)
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- Pd-catalyzed oxidative Heck-type arylation of vinyl ketones, alkenes, and acrylates with Sb-aryl-tetrahydrodibenz[c,f][1,5]azastibocines
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The Pd-catalyzed cross-coupling reactions of Sb-aryl-1,5-azastibocines with alkenes are described. The reactions of azastibocines with alkenes such as vinyl ketones, alkenes, and acrylates in the presence of 10 mol% PdCl2 at 80 °C in DMA under aerobic conditions produced Heck adducts in moderate-to-excellent yields. Single-crystal X-ray and NMR analysis revealed that the aryl donors in this reaction, the Sb-aryl-1,5-azastibocines, are hypervalent compounds that display N–Sb intramolecular non-bonding interaction. These are the first examples of Pd-catalyzed Heck-type arylations using heterocyclic hypervalent organoantimony compounds. Although the reactions proceeded efficiently with the azastibocines, they hardly progressed with trivalent and pentavalent triarylantimony reagents.
- Murata, Yuki,Kakusawa, Naoki,Arakawa, Yukako,Hayashi, Yukako,Morinaga, Shun,Ueda, Masaaki,Hyodo, Tadashi,Matsumura, Mio,Yamaguchi, Kentaro,Kurita, Jyoji,Yasuike, Shuji
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- Fluoride anion-initiated bis-trifluoromethylation of phenyl aromatic carboxylates with (trifluoromethyl)trimethylsilane
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The fluoride anion-initiated reaction of phenyl aromatic carboxylates with (trifluoromethyl)trimethylsilane (Me3SiCF3) that results in the formation of O-silyl-protected 2-aryl-1,1,1,3,3,3-hexafluoroisopropanols is reported. A phenoxide anion, generated during the trifluoromethylation of the phenyl carboxylate, also activates the Me3SiCF3, which permits a catalytic amount of the fluoride anion source to be used. Various functional groups, which can be used for further elaboration, are tolerated in the reaction.
- Takahashi, Kenjiro,Ano, Yusuke,Chatani, Naoto
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supporting information
p. 11661 - 11664
(2020/10/19)
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- Recyclable Pd ionic catalyst coated on cordierite monolith for high TOF Heck coupling reaction
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Abstract : Pd 2 + ionic catalyst, Ti 0.97Pd 0.03O 1.97 was coated over cordierite monolith by solution combustion method. The catalyst coated on the cordierite is nano-crystalline as seen from XRD studies. Coated catalyst was used for Heck coupling reactions with different substrates of aryl halides and olefins. Thus handling nano-crystalline catalyst powder is avoided by fixing it on a solid catalyst cartridge. Heck coupled products were characterized using 1H NMR, 13C NMR, Mass and FTIR spectroscopy. This catalyst showed high selectivity towards Heck coupling reaction. Turnover frequencies (TOF) for each of the reactions were found to be very high. The catalyst was recycled up to 7 times with total TOF 3017 h - 1, which is found to be a new green technique in the Heck coupling reaction. Graphical abstract: Ti 0.97Pd 0.03O 1.97 catalyst is coated on cordierite monolith honeycomb (HC) by solution combustion method and it is used in the Heck coupling reaction. Reactions are done in a specially designed flask. Catalyst is recycled for 7 times. The total turnover frequency (TOF) after 7 cycles was 3017 h - 1. [Figure not available: see fulltext.].
- Bhat, Shrikanth K,Prasad, Jagadeesh D,Hegde
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- Enol Ester Intermediate Induced Metal-Free Oxidative Coupling of Carboxylic Acids and Arylboronic Acids
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A facile, efficient and environmentally friendly methodology for the preparation of phenolic esters is realized via metal-free coupling of carboxylic acids and arylboronic acids. This sequential one pot reaction, employing methyl propiolate as an activating reagent, proceeds through the formation of enol ester intermediate, followed by a nucleophilic attack on the C-O bond under the oxidation of hydrogen peroxide. These studies display that enol esters, despite previously being overlooked as synthetic intermediates, would be the valuable building blocks for developing carbon–carbon and carbon–heteroatom bond-forming reactions.
- Xu, Xianjun,Feng, Huangdi,Li, Huiqiong,Huang, Liliang
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p. 3921 - 3928
(2019/06/24)
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- Exploring the influence of designer surfactant hydrophobicity in key C–C/C–N bond forming reactions
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Designer micellar medium was explored for the transformation of diverse anilines to the corresponding densely substituted biologically relevant skatole derivatives in an aqueous medium via 5-exo-trig cyclization reaction. The scope of the reaction was extended to intermolecular Csp2-Csp2 and Csp2-N bond forming reactions in water. Systematic investigations revealed that altering hydrophobicity of surfactant influences the yield of both C–C and C–N bond forming reactions in water.
- Reddy, Singarajanahalli Mundarinti Krishna,Kothandapani, Jagatheeswaran,Sengan, Megarajan,Veerappan, Anbazhagan,Selva Ganesan, Subramaniapillai
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- Bioactivity and structure–activity relationship of cinnamic acid derivatives and its heteroaromatic ring analogues as potential high-efficient acaricides against Psoroptes cuniculi
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A series of cinnamic acid derivatives and its heteroaromatic ring analogues were synthesized and evaluated for acaricidal activity in vitro against Psoroptes cuniculi, a mange mite. Among them, eight compounds showed the higher activity with median lethal concentrations (LC50) of 0.36–1.07 mM (60.4–192.1 μg/mL) and great potential for the development of novel acaricidal agent. Compound 40 showed both the lowest LC50 value of 0.36 mM (60.4 μg/mL) and the smallest median lethal time (LT50) of 2.6 h at 4.5 mM, comparable with ivermectin [LC50 = 0.28 mM (247.4 μg/mL), LT50 = 8.9 h], an acaricidal drug standard. SAR analysis showed that the carbonyl group is crucial for the activity. The type and chain length of the alkoxy in the ester moiety and the steric hindrance near the ester group significantly influence the activity. The esters were more active than the corresponding thiol esters, amides, ketones or acids. Replacement of the phenyl group of cinnamic esters with α-pyridyl or α-furanyl significantly increase the activity. Thus, a series of cinnamic esters and its heteroaromatic ring analogues with excellent acaricidal activity emerged.
- Chen, Dong-Dong,Zhang, Bing-Yu,Liu, Xiu-Xiu,Li, Xing-Qiang,Yang, Xin-Juan,Zhou, Le
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supporting information
p. 1149 - 1153
(2018/03/05)
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- Transesterification of (hetero)aryl esters with phenols by an Earth-abundant metal catalyst
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Readily available and inexpensive Earth-abundant alkali metal species are used as efficient catalysts for the transesterification of aryl or heteroaryl esters with phenols which is a challenging and underdeveloped transformation. The simple conditions and the use of heterogeneous alkali metal catalyst make this protocol very environmentally friendly and practical. This reaction fills in the missing part in transesterification reaction of phenols and provides an efficient approach to aryl esters, which are widely used in the synthetic and pharmaceutical industry.
- Chen, Jianxia,Namila,Bai, Chaolumen,Baiyin, Menghe,Agula, Bao,Bao, Yong-Sheng
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p. 25168 - 25176
(2018/07/29)
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- Hexafluoroisopropanol and Acetyl Chloride Promoted Catalytic Hydroarylation with Phenols
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We report a catalytic hydroarylation method to convert phenols to dihydrocoumarins in hexafluoroisopropanol (HFIP) using acid generated from sub-stoichiometric amounts of acetyl chloride as catalyst. Attractive elements include easy set-up and isolation, and applicability to a range of phenols including natural product substrates.
- Roy, Sudeshna,Motiwala, Hashim F.,Koshlap, Karl M.,Aubé, Jeffrey
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supporting information
p. 306 - 315
(2017/12/07)
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- Method of coupling, and the coupling method using the aromatic group-substituted heterocyclic compound
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Provided is an easy method (coupling method) capable of easily synthesizing a compound group in which aromatic molecules and aromatic molecules are coupled, a compound group in which aromatic molecules and alkene molecules are coupled, and the like without producing halogen waste and without the need to use scarce and expensive palladium. A compound (A) shown by general formula (A): Ar-H and a compound (B1) shown by general formula (B1): RaOCO-Ar', a compound (B2) shown by general formula (B2): RbCH=C(Ar")2, or a compound (B3) shown by general formula (B3): RcOCOCH=C(Ar")2 are reacted in the presence of a nickel compound.
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-
Paragraph 0220-0222
(2020/09/17)
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- Chalcone and cinnamate synthesis via one-pot enol silane formation-Mukaiyama aldol reactions of ketones and acetate esters
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Aryl alkyl ketones, acetate esters, and acetamides undergo facile one-pot enol silane formation, Mukaiyama aldol addition, and dehydrosilyloxylation in the presence of an amine base and excess trimethylsilyl trifluoromethanesulfonate. The chalcone and cinnamate products are generally recovered in high yield. The relative stoichiometry of the trimethylsilyl trifluoromethanesulfonate and amine base reagents determines whether the reaction yields the β-silyloxy carbonyl product or the α,β-unsaturated carbonyl.
- Downey, C. Wade,Glist, Hadleigh M.,Takashima, Anna,Bottum, Samuel R.,Dixon, Grant J.
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supporting information
p. 3080 - 3083
(2018/07/06)
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- An ionic liquid catalyzed probase method for one-pot synthesis of α,β-unsaturated esters from esters and aldehydes under mild conditions
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A one-pot synthesis of α,β-unsaturated esters from unactivated esters and aldehydes using strong bases, such as sodium alkoxide and potassium tert-butoxide, was reported. However, the ionic liquid (IL) catalyzed probase method for producing α,β-unsaturated esters was not reported until now. In this work, a series of ILs with fluoride anions were firstly prepared and used as catalysts in combination with the probase N,O-bis(trimethylsilyl) acetamide (BSA) for the α,β-unsaturated esters synthesis. This process could also be promoted through the introduction of another IL with Lewis acid sites. The yield and selectivity of the product could reach up to 84.2% and 95.0%, respectively, when [Bmim]F was used in combination with [Bmim]Cl/AlCl3 (the molar fraction of AlCl3 is 0.67). The mechanism investigation through GC-MS indicates that BSA would convert into onium amide, which acted as a strong base for α-H abstraction, with the catalysis of [Bmim]F. Meanwhile, [Bmim]Cl/AlCl3 played an important role in the condensation step between enolates and aldehydes. On the basis of mechanism insights, kinetic and thermodynamic studies were also carried out for a better understanding of this new route.
- Wang, Gang,Xu, Yiming,Zhang, Suojiang,Li, Zengxi,Li, Chunshan
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p. 4838 - 4848
(2017/10/23)
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- Bioactivity and structure-activity relationship of cinnamic acid esters and their derivatives as potential antifungal agents for plant protection
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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
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- Metal-Free O-Arylation of Carboxylic Acid by Active Diaryliodonium(III) Intermediates Generated in situ from Iodosoarenes
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The metal-free arylative coupling of carboxylic acids using iodosoarenes without the use of a catalyst and base, which is applicable to even a highly-polar molecule bearing multiple alcohol groups, is reported. The in situ preparation of the reactive diaryliodonium(III) carboxylates is the important key to this approach, and the introduction of the trimethoxybenzene auxiliary enables both the smooth salt formations and the selective aryl transfer events during the couplings. (Figure presented.).
- Dohi, Toshifumi,Koseki, Daichi,Sumida, Kohei,Okada, Kana,Mizuno, Serina,Kato, Asami,Morimoto, Koji,Kita, Yasuyuki
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supporting information
p. 3503 - 3508
(2017/09/13)
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- Iodobenzene Dichloride in the Esterification and Amidation of Carboxylic Acids: In-Situ Synthesis of Ph3PCl2
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A novel, in-situ synthesis of dichlorotriphenylphosphorane (Ph3PCl2) is accomplished upon combining PPh3and the easily prepared hypervalent iodine reagent iodobenzene dichloride (PhICl2). The phosphorane is selectively generated in the presence of carboxylic acid or alcohol residues to rapidly produce acyl chlorides and alkyl chlorides in high yields. Addition of EtOH, PhOH, BnOH, Et2NH or CH2N2results in the direct synthesis of esters, amides and diazo ketones from carboxylic acids.
- Carle, Myriam S.,Shimokura, Grace K.,Murphy, Graham K.
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supporting information
p. 3930 - 3933
(2016/08/24)
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- BF3·OEt2-mediated: Syn -selective Meyer-Schuster rearrangement of phenoxy propargyl alcohols for Z -β-aryl-α,β-unsaturated esters
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Synthesis of Z-β-aryl-α,β-unsaturated esters from readily available 1-aryl-3-phenoxy propargyl alcohols is achieved via a BF3-mediated syn-selective Meyer-Schuster rearrangement under ambient conditions. The reaction mechanism is postulated to involve an electrophilic borylation of an allene intermediate as the key step to kinetically control the stereoselectivity.
- Puri, Surendra,Hari Babu, Madala,Sridhar Reddy, Maddi
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p. 7001 - 7009
(2016/07/30)
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- Negative-type photosensitive resin composition, pattern forming method, cured film, insulating film, color filter, and display device
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A negative-type photosensitive resin composition capable of forming a pattern having favorable adhesiveness at a low light exposure; a pattern forming method using the resin composition; a cured film, an insulating film, a color filter formed using resin composition; and a display device provided with the cured film, insulating film, or color filter. The resin composition contains a compound represented by the following formula (1). In the formula, R1 and R2 each independently indicate a hydrogen atom or an organic group, but at least one indicates an organic group. R1 and R2 may be bonded to form a ring structure and may contain a hetero atom bond. R3 indicates a single bond or an organic group. R4 to R9 each independently indicate a hydrogen atom, an organic group, etc., but R6 and R7 are never hydroxyl groups. R10 indicates a hydrogen atom or an organic group.
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- Palladium-catalyzed aerobic oxidative double allylic C-H oxygenation of alkenes: A novel and straightforward route to α,β-unsaturated esters
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A mild tandem oxidative functionalization of allyl aromatic hydrocarbons was accomplished using the catalytic system of Pd(OAc)2/DMA under 1 atm O2. The green twofold C-O bond formation involving double allylic C-H oxygenation unlocks opportunities for markedly different synthetic strategies. Moreover, the reaction affords aryl α,β-unsaturated esters directly from readily available terminal olefins in moderate to good yields with excellent chemo- and stereoselectivities.
- Yang, Wanfei,Chen, Huoji,Li, Jianxiao,Li, Chunsheng,Wu, Wanqing,Jiang, Huanfeng
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supporting information
p. 9575 - 9578
(2015/06/08)
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- Thiophosphoramides as cooperative catalysts for copper-catalyzed arylation of carboxylates with diaryliodonium salts
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A thiophosphoramide-based co-catalyst was found to significantly accelerate copper(ii) trifluoromethanesulfonate-catalyzed arylation of potassium carboxylates with diaryliodonium salts. This effect could be attributed to counterion activation of diaryliodonium salts or organocopper intermediates by thiophosphoramides. Inclusion of thiophosphoramides permits achieving significantly milder reaction conditions and expands the scope of solvents and diaryliodonium counterions that could be used for the arylation of carboxylate nucleophiles.
- Bhattarai, Bijay,Tay, Jia-Hui,Nagorny, Pavel
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supporting information
p. 5398 - 5401
(2015/03/30)
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- Metal-free synthesis of aryl esters by coupling aryl carboxylic acids and aryl boronic acids
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A facile synthesis of aryl esters is developed by coupling aryl carboxylic acids and aryl boronic acids in the presence of PhI(OAc)2 and carbonyl diimidazole. A wide range of functional groups were tolerant to the metal-free reaction condition that led to the desired products in good yields.
- Ruso, Jayaraman Sembian,Rajendiran, Nagappan,Kumaran, Rajendran Senthil
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supporting information
p. 2345 - 2347
(2014/05/06)
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- N-heterocyclic carbene-catalyzed oxidation of aldehydes for the synthesis of amides via phenolic esters
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N-heterocyclic carbene-catalyzed oxidation using TEMPO is reported for the conversion of aldehydes to amides. A wide range of amides were synthesized in good yields (up to 72%) via a one-pot, sequential protocol involving oxidative esterification of aldehydes and subsequent aminolysis. To promote efficient aminolysis, various alkoxide leaving groups were evaluated.
- Ji, Miran,Lim, Seungyeon,Jang, Hye-Young
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p. 28225 - 28228
(2014/07/22)
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- N-heterocyclic carbene catalysed oxidative coupling of aldehydes with alcohols/thiols and one-pot oxidation/esterification of allylic alcohols
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A versatile carbene-catalysed oxidation protocol involving N-heterocyclic carbene catalysts and 2,2,6,6-tetramethylpiperidine N-oxyl (TEMPO) is described for the synthesis of esters, cinnamic acids, and thioesters. A wide range of esters, thioesters, and cinnamic acids were obtained by metal-free coupling of aldehydes with aliphatic, allylic and aromatic alcohols, benzyl mercaptan, and water. In addition to the oxidative coupling of aldehydes with nucleophiles, dehydrogenation of saturated aldehydes and oxidation of allylic alcohols were found under our oxidative coupling conditions. Unlike other TEMPO-mediated oxidative esterification reactions, this reaction does not proceed through a TEMPO ester intermediate to form esters and thioesters. N-Heterocyclic carbene complexes catalyse various oxidative coupling reactions in the presence of TEMPO. A variety of α,β-unsaturated and saturated esters, and aromatic esters and thioesters were synthesised. Copyright
- Ji, Miran,Wang, Xi,Lim, Yu Na,Kang, Ye-Won,Jang, Hye-Young
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supporting information
p. 7881 - 7885
(2014/01/06)
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- Structure-reactivity correlations in nucleophilic displacement reactions of Y-substituted-phenyl X-substituted-cinnamates with Z-substituted-phenoxides
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Second-order rate constants (kN) have been measured spectrophotometrically for the nucleophilic displacement reactions of 4-nitrophenyl X-substituted-cinnamates (4a-4e) and Y-substituted-phenyl cinnamates (5a-5e) with Z-substituted-phenoxide anions in 80 mol % H2O/20 mol % DMSO at 25.0 ±0.1 °C. The Hammett plot for the reactions of 4a-4e with 4-chlorophenoxide (4-ClPhO.) consists of two intersecting straight lines, which might be taken as a change in the rate-determining step (RDS). However, it has been concluded that the nonlinear Hammett plot is not due to a change in the RDS but is caused by stabilization of the ground state of substrates possessing an electron-withdrawing group in the cinnamoyl moiety through resonance interactions, since the Yukawa-Tsuno plot exhibits an excellent linear correlation with ρX = 0.89 and r = 0.58. The Bronsted-type plot for the reactions of 4-nitrophenyl cinnamate (4c) with Z-substituted-phenoxides is linear with βnuc = 0.76. The Bronsted-type plot for the reactions of Y-substituted-phenyl cinnamates (5a-5d) with 4-chlorophenoxides (4-ClPhO.) is also linear with βlg =.0.72. The Hammett plot correlated with σ-. constants for the reactions of 5a-5d results in a much better linear correlation than that correlated with σo constants, indicating that a partial negative charge develops on the O atom of the leaving aryloxide. Thus, the reactions have been concluded to proceed through a concerted mechanism.
- Son, Yu-Jin,Kim, Eun-Hee,Kang, Ji-Sun,Um, Ik-Hwan
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p. 2455 - 2460
(2013/09/24)
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- An efficient palladium(II) catalyst for oxidative Heck-type reaction under base-free conditions
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An efficient catalytic system for the palladium-catalyzed oxidative Heck reaction between arylboronic acids and various alkenes has been developed. Using the bis(aminoalkoxy)palladium complex of N,N-dimethylethanolamine as a catalyst, a series of substituted alkenes were obtained in moderate to excellent yields under mild reaction conditions. This protocol could be tolerated to arylboronic acids containing electron-donating or withdrawing groups and a wide range of olefins, such as acrylate, allyl esters, allyl ethers and alkenylphosphonate. A plausible reaction mechanism of the oxidative Heck reaction was proposed.
- Mi, Xia,Huang, Mengmeng,Guo, Hai,Wu, Yangjie
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p. 5123 - 5128
(2013/06/27)
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- C-H alkenylation of azoles with enols and esters by nickel catalysis
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Rather u(Ni)que: Two new C-H alkenylation reactions, that is C-H/Ci£O alkenylation and decarbonylative C-H alkenylation, of azoles are uniquely catalyzed by Ni/dcype. These azole alkenylation reactions are successfully applied to the convergent formal synthesis of siphonazoleB.
- Meng, Lingkui,Kamada, Yuko,Muto, Kei,Yamaguchi, Junichiro,Itami, Kenichiro
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supporting information
p. 10048 - 10051
(2013/10/01)
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- Influence of electronically and sterically tunable cinnamate ligands on the spectroscopic, kinetic, and thermodynamic properties of bis(triphenylphosphine) palladium(0) olefin complexes
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A detailed study of the influence of electronic and steric characteristics of cinnamic acid esters on the spectroscopic, kinetic, and thermodynamic properties of bis(triphenylphosphine)palladium(0) cinnamic acid ester complexes is presented (51 different new complexes included). These complexes show a dynamic behavior on the NMR spectroscopic time scale. Therefore, the rotational barriers of the olefin about the metalolefin bond as well as the dissociation entropy and enthalpy of the olefin and the dissociation mechanism could be determined. These findings are interpreted together with the NMR spectroscopic, IR spectroscopic, and X-ray structural data (7 new structures included) concerning the influence of the different olefin ligands on the complex properties by means of Hammett plots. DFT calculations were performed to support the mechanistic conclusions.
- Buchner, Magnus R.,Bechlars, Bettina,Wahl, Bernhard,Ruhland, Klaus
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experimental part
p. 588 - 601
(2012/03/22)
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- TMSOTf-catalyzed intramolecular seleno-arylation of tethered alkenes: A novel method for the solid-phase synthesis of dihydrocoumarins and coumarins
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TMSOTf-catalyzed intramolecular seleno-arylation of tethered alkenes was performed using polystyrene-supported succinimidyl selenide as the selenium source. This catalytic process provides an efficient method for the regioselective synthesis of dihydrocoumarins possessing a seleno-functionality, followed by traceless cleavage of selenium linker to provide dihydrocoumarins and coumarins in good yields and purities.
- Tang,Li, Wen,Gao, Zhang Yong,Gu, Xi
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body text
p. 631 - 634
(2012/07/03)
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- Palladium-catalyzed aerobic oxidative coupling of acyl chlorides with arylboronic acids
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The first example of a palladium-catalyzed aerobic oxidative coupling of acyl chlorides with arylboronic acids has been developed, leading to a wide range of aryl benzoates in good to excellent yields. This catalytic system shows broad functional group tolerance. Preliminary mechanistic experiments using deuterium labeling showed that the oxygen atom was derived from dioxygen. Copyright
- Chen, Jiuxi,Peng, Yong,Liu, Miaochang,Ding, Jinchang,Su, Weike,Wu, Huayue
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supporting information
p. 2117 - 2122
(2012/11/07)
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- Preparation of α,β-unsaturated esters and amides via external-CO-free palladium-catalyzed carbonylation of alkenyl tosylates
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Palladium-catalyzed carbonylation of tosylates with phenyl formate is described. This procedure needs neither external carbon monoxide nor any pressure-resistant apparatus. A variety of cyclic and acyclic alkenyl tosylates can be converted into the corresponding phenyl esters in good yields. Furthermore, this method is effective for the one-pot synthesis of α,β-unsaturated amides.
- Ueda, Tsuyoshi,Konishi, Hideyuki,Manabe, Kei
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supporting information; experimental part
p. 5171 - 5175
(2012/09/25)
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- Nucleophilic carbene-catalyzed redox-esterification reaction of α-halo-α,β-unsaturated aldehyde
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A nucleophilic carbene catalyzed redox esterification between α-halo-α,β-unsaturated aldehydes and various alcohols has been developed. Interestingly, the reaction provided α,β-unsaturated esters instead of the saturated α-halo substituted esters as the only product in good to high yield with excellent trans-selectivity, presumably via the umpolung-halo-elimination pathway.
- Wang, Xiang-Bo,Zou, Xiao-Lei,Du, Guang-Fen,Liu, Zhi-Yong,Dai, Bin
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p. 6498 - 6503
(2012/08/27)
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- NHC-catalyzed C-O or C-N bond formation: Efficient approaches to α,β-unsaturated esters and amides
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Simple and efficient NHC-catalyzed transformations of bromoenal or α,β-dibromoenal into α,β-unsaturated esters or amides with high stereoselectivity through C-O or C-N bond formation have been demonstrated. The NHC-catalyzed processes occur under mild con
- Zhang, Bo,Feng, Peng,Cui, Yuxin,Jiao, Ning
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supporting information; experimental part
p. 7280 - 7282
(2012/07/28)
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- Palladium-catalyzed carbonylation of aryl, alkenyl, and allyl halides with phenyl formate
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Highly efficient palladium-catalyzed carbonylation of aryl, alkenyl, and allyl halides with phenyl formate is reported. This procedure does not use carbon monoxide and affords one-carbon-elongated carboxylic acid phenyl esters in excellent yields. The reaction proceeds smoothly under mild conditions and tolerates a wide range of functional groups including aldehyde, ether, ketone, ester, and cyano groups. Furthermore, a variety of heteroaromatic bromides can be converted to the corresponding phenyl esters in high yields.
- Ueda, Tsuyoshi,Konishi, Hideyuki,Manabe, Kei
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p. 3100 - 3103
(2012/07/27)
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- Dinuclear zinc catalyzed asymmetric spirannulation reaction: An umpolung strategy for formation of α-alkylated-α-hydroxyoxindoles
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A highly diastereo- and enantioselective formal [3 + 2] cycloaddition of α,β-unsaturated esters and 3-hydroxyoxindoles catalyzed by a dinuclear zinc-ProPhenol complex is reported. The stereoselective Michael additions of 3-hydroxyoxindoles and the subsequent transesterifications afford spirocyclic δ-lactones.
- Trost, Barry M.,Hirano, Keiichi
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p. 2446 - 2449
(2012/07/27)
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- N-Heterocyclic carbene catalysed aerobic oxidation of aromatic aldehydes to aryl esters using boronic acids
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The organocatalytic behavior of N-heterocyclic carbenes in the aerobic oxidation of aromatic aldehydes to esters with boronic acids has been explored. This transition metal-free protocol allows access to a wide variety of aromatic esters in good to excellent yields under mild reaction conditions.
- Arde, Panjab,Ramanjaneyulu,Reddy, Virsinha,Saxena, Apurv,Anand, R. Vijaya
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supporting information; experimental part
p. 848 - 851
(2012/02/05)
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- Pd-catalysed decarboxylative Suzuki reactions and orthogonal Cu-based O-arylation of aromatic carboxylic acids
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Pd-catalysed decarboxylative Suzuki reactions and orthogonal Cu-based O-arylation reactions of aromatic carboxylic acids are reported. The new reactions may provide alternative routes for the synthesis of some biaryls and aromatic carboxylic esters. The Royal Society of Chemistry 2011.
- Dai, Jian-Jun,Liu, Jing-Hui,Luo, Dong-Fen,Liu, Lei
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supporting information; experimental part
p. 677 - 679
(2011/03/22)
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- Selective synthesis of 3,4-dihydrocoumarins and chalcones from substituted aryl cinnamic esters
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Coumarins are ubiquitous in plant kingdom and have been used as antitumor, antifungals, anticoagulants, insecticides. Chalcones are also widespread in plant kingdom and have been known to possess diverse biological activities; antibacterial, antifungal, antitumor and anti-inflammatory, etc. As they are considered as important natural products, numerous synthetic approaches have been reported up to the present. We devise a new selective method of preparing dihydrocoumarins and chalcones from aryl cinnamates by the selection of reagents. Dihydrocoumarin derivatives were prepared selectively by using intramolecular cyclization catalyzed by p-toluene sulfonic acid. Also, chalcones were prepared by Fries-rearrangement catalyzed by TiCl4. This method can be used for preparing various coumarin & chalcone compounds.
- Jeon, Jae-Ho,Yang, Deok-Mo,Jun, Jong-Gab
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experimental part
p. 65 - 70
(2011/10/31)
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- NHC/Iron cooperative catalysis: Aerobic oxidative esterification of aldehydes with phenols
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An NHC/iron cooperative catalytic system mediates the aerobic oxidative esterification of aldehydes with phenols. The use of equimolar amounts of reactants led to good to excellent isolated yields of esters.
- Reddy, R. Sudarshan,Rosa, Joao N.,Veiros, Luis F.,Caddick, Stephen,Gois, Pedro M. P.
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supporting information; experimental part
p. 3126 - 3129
(2011/05/12)
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- Molybdenum hexacarbonyl mediated alkoxycarbonylation of aryl halides
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Mo(CO)mediates the alkoxycarbonylation of aryl halides in their reaction with alcohols to afford arenecarboxylic acid esters. The molybdenum carbonyl complexes act as the catalyst and the source with carbon monoxide. The alkoxycarbonylation proceeds with a small excess of carbon monoxide in the form of Mo(CO)and the procedure is simple compared to the conventional method, which uses palladium catalyst under gaseous carbon monoxide. Using this procedure, a variety of carboxylic acid esters were prepared. Georg Thieme Verlag Stuttgart ? New York.
- Ren, Wei,Emi,Yamane, Motoki
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experimental part
p. 2303 - 2309
(2011/09/19)
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- Cu(OTf)2-mediated Chan-Lam reaction of carboxylic acids to access phenolic esters
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A Cu(OTf)2-mediated Chan-Lam reaction of carboxylic acids with arylboronic acids is described. It represents a facile and practical methodology to access phenolic esters in moderate to good yields. The procedure tolerates a series of functional groups, such as methoxycarbonyl, acetoxy, free phenolic hydroxyl, vinyl, nitro, trifluoromethyl, methoxyl, bromo, chloro, iodo, and acetyl groups.
- Zhang, Lingli,Zhang, Guoying,Zhang, Manli,Cheng, Jiang
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experimental part
p. 7472 - 7474
(2011/01/03)
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- Novel molecular hybrids of cinnamic acids and guanylhydrazones as potential antitubercular agents
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In an attempt to identify potential new agents active against tuberculosis, 20 novel phenylacrylamide derivatives incorporating cinnamic acids and guanylhydrazones were synthesized using microwave assisted synthesis. Activity of the synthesized compounds was evaluated using resazurin microtitre plate assay (REMA) against Mycobacterium tuberculosis H37Rv. Based on empirical structure-activity relationship data it was observed that both steric and electronic parameters play major role in the activity of this series of compounds. Compound 7s (2E)-N-((-2-(3,4-dimethoxybenzylidene) hydrazinyl) (imino) methyl)-3-(4-methoxyphenyl) acrylamide showed MIC of 6.49 μM along with good safety profile of >50-fold in VERO cell line. Thus, this compound could act as a potential lead for further antitubercular studies.
- Bairwa, Ranjeet,Kakwani, Manoj,Tawari, Nilesh R.,Lalchandani, Jaya,Ray,Rajan,Degani, Mariam S.
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supporting information; experimental part
p. 1623 - 1625
(2010/06/16)
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- Copper(II)-catalyzed esterification of arenecarboxylic acids with aryl- and vinyl-substituted trimethoxysilanes
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In this paper, the copper(II)-catalyzed esterification reaction of arenecarboxylic acids with aryl- or vinyl-substituted trimethoxysilanes is described. A series of aryltrimethoxysilanes and arenecarboxylic acids worked well under this procedure, affording aryl benzoate derivatives in moderate to good yields. Notably, trimethoxy(vinyl)silanes also worked well under this procedure giving a facile and versatile method to access vinyl benzoate derivatives. Georg Thieme Verlag Stuttgart.
- Luo, Fang,Pan, Changduo,Qian, Pengcheng,Cheng, Jiang
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supporting information; experimental part
p. 2005 - 2010
(2010/08/19)
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