bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design of Carbon Nanotube‐Based Gas‐Diffusion Cathode for O2 Reduction by Multicopper Oxidases
Authors: Lau Carolin , Adkins Emily R. , Ramasamy Ramaraja P. , Luckarift Heather R. , Johnson Glenn R. , Atanassov Plamen 
Published: December 2011

AbstractMulticopper oxidases, such as laccase or bilirubin oxidase, are known to reduce molecular oxygen at very high redox potentials, which makes them attractive biocatalysts for enzymatic cathodes in biological fuel cells. By designing an enzymatic gas‐diffusion electrode, molecular oxygen can be supplied through the gaseous phase, avoiding solubility and diffusion limitations typically associated with liquid electrolytes. In doing so, the current density of enzymatic cathodes can theoretically be enhanced. This publication presents a material study of carbon/Teflon composites that aim to optimize the functionality of the gas‐diffusion and catalytic layers for application in enzymatic systems. The modification of the catalytic layer with multiwalled carbon nanotubes, for example, creates the basis for stronger π–π stacking interactions through tethered enzymatic linkers, such as pyrenes or perylene derivates. Cyclic voltammograms show the effective direct electron contact of laccase with carbon nanotube‐modified electrodes via tethered crosslinking molecules as a model system. The polarization behavior of laccase‐modified gas‐diffusion electrodes reveals open‐circuit potentials of +550 mV (versus Ag/AgCl) and current densities approaching 0.5 mA cm2 (at zero potential) in air‐breathing mode.
Engineering properties of compatibilized polypropylene/liquid crystalline polymer blends
Authors: Mandal P. K. , Siddhanta S. K. , Chakraborty D. 
Published: December 2011

AbstractPolypropylene (PP) and Vectra A950, a thermotropic liquid crystalline polymer (LCP), blends were prepared in a single‐screw extruder with the variation in Vectra A950 content in presence of fixed amount (2%, with respect to PP and LCP mixture as a whole) of ethylene‐acrylic acid (EAA) copolymer as a compatibilizer. Mechanical analysis of the compatibilized blends within the range of LCP incorporations under study (2–10%) indicated pronounced improvement in the moduli, ultimate tensile strength (UTS), and hardness. Fourier transform infrared (FTIR) spectroscopy studies revealed the presence of strong interaction through H‐bonding between the segments of Vectra A950 and the compatibilizer EAA. Morphological studies performed by scanning electron microscopy (SEM) manifested the development of fine fibrillar morphology in the compatibilized PP/Vectra A950 blends, which had large influence on the mechanical properties. Differential scanning calorimetry studies showed an initial drop of the melting point of PP in the presence of EAA followed by enhancement of the same in presence of Vectra A950. TGA showed an increase in the thermal stability for all blends with respect to matrix polymer PP. Rheological studies showed that a very small quantity of Vectra A 950 was capable of reducing the melt viscosity of PP particularly in the lower shear rate region and hence facilitated processibility of the blends. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Recycling studies of marble processing waste: Composites based on commercial epoxy resin
Authors: Ahmetli Gulnare , Dag Mustafa , Deveci Huseyin , Kurbanli Refika 
Published: December 2011

AbstractMarble waste was obtained from marble processing plant wastewater with precipitation using different coagulants, such as sepiolite, zeolite, and pumice in dosages of 0.5–8 g/500 mL and mixed in 20 wt % with commercial epoxy resin. The effects of marble, coagulant type and dosage on the physicomechanical and thermal properties were investigated. The incorporation of marble processing waste particles increases the 10% decomposition temperature of pure epoxy by 5–50°C. Surface hardness, tensile strength, percentage elongation, and stress at maximum load of the composites were higher than those of pure resin, too. The composites reinforced with marble processing waste‐pumice showed about 10% increase in elastic modulus, whereas the composite reinforced with marble processing waste‐sepiolite or zeolite showed about 76.67–143.33% increase in elastic modulus over the pure epoxy matrix. Scanning electron microscopy (SEM) was used for characterization of surface and cross sections of the composites to verify the results. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
N‐(n‐Alkyl)‐2‐pyridinemethanimine mediated atom transfer radical polymerization of lauryl methacrylate: Effect of length of alkyl group
Authors: Srivastava Pravin Kumar , Choudhary Veena 
Published: December 2011

AbstractThe article describes the polymerization of lauryl methacrylate (LMA) using Cu(I)Br as catalyst for atom transfer radical polymerization in conjunction with N‐(n‐propyl) [PPMI]/(n‐hexyl) [HPMI]/(n‐octyl) [OPMI]‐2‐pyridinemethanimine as complex ligands. The polymerization of LMA was investigated in bulk and solution (toluene as solvent) using Cu(I)Br as catalyst, N‐(n‐alkyl)‐2‐pyridinemethanimine as ligands and ethyl‐2‐bromo isobutyrate (EBiB) as initiator. The ratio of LMA : CuBr : Ligand : EBiB was kept constant in all the polymerizations. In bulk polymerization, the solubility of the catalyst complex increased with increasing the length of alkyl chain on the ligand from propyl to octyl and also gave polymers with narrow molecular weight distribution. The PDI was further narrowed by using OPMI as ligand and toluene was used as solvent. The kinetics of polymerization was also analyzed and it clearly shows that % conversion increased with time. Increase in molecular weight with % conversion without affecting PDI clearly show that the system is living and living nature can be controlled by increasing the length of alkyl group. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Epoxy resin/polymer blends: Improvement of thermal and mechanical properties
Authors: Ahmetli Gulnare , Deveci Huseyin , Soydal Ulku , Gurler Sevgi Pıstıl , Altun Ahmet 
Published: December 2011

AbstractFatty acid waste was recycled as raw material and utilized to synthesize epoxy (HP) or unsaturated ester group (OEE) containing polymers. The radicalic polymerization between the styrene and itaconic acid was carried out, too. Glycidyl ester of styrene‐itaconic acid copolymer was obtained by esterification reaction with epichlorohydrin. The polymers were characterized by means of Fourier transform infrared spectroscopy and chemical analysis. The polymers were incorporated into diglycidyl ether of bisphenol A type commercial epoxy resin to prepare composites. The effects of polymer structure and amount on the physico‐mechanical and thermal properties of epoxy were investigated. Surface hardness, tensile strength, percentage elongation and stress at maximum load of the composites were obtained higher than pure epoxy resin. The composites reinforced with bio‐based polymers showed about 74.55–243% increase in elastic modulus over the pure epoxy matrix. Obtained Young's modulus values were higher for composites with styrene‐based polymers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Water structure in poly(2‐hydroxyethyl methacrylate): Effect of molecular weight of poly(2‐hydroxyethyl methacrylate) on its property related to water
Authors: Mochizuki Akira , Ogawa Haruki , Nishimori Yusuke 
Published: December 2011

AbstractLow molecular weight poly(2‐hydroxyethyl methacrylate) (polyHEMA) with a number average molecular weight (Mn) <22,600, were prepared by atom transfer radical polymerization. The molecular weight and end groups of the polyHEMA were varied, and the water content equilibrium moisture sorption and water structure were analyzed using differential scanning calorimetry (DSC) and X‐ray diffractometry (XRD). Higher water content was observed for polyHEMA with Mn < 10,000. DSC revealed that the amounts of nonfreezing water are affected neither by the molecular weight nor by the end groups of the polyHEMA. On the other hand, the amount of freezing water was affected by both the molecular weight and end groups of polyHEMA, especially for polyHEMA with Mn < 20,000. The XRD‐DSC measurements showed that water in polyHEMA form hexagonal ice and that the direction of crystal growth is dependent on the molecular weight. These findings indicate that the molecular weight of polyHEMA plays a significant role in the water structure in polyHEMA. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Telocytes in Parotid Glands
Authors: Nicolescu Mihnea I. , Bucur Alexandru , Dinca Octavian , Rusu Mugurel C. , Popescu Laurentiu M. 
Published: December 2011

AbstractThe parotid histological structure includes acinar, ductal, and myoepithelial cells, surrounded by a connective stromal component. The parotid stroma is mostly regarded as an inert shell, consisting of septa, which divide the parenchyma. Telocytes were recently identified as a new stromal cell type in various organs, including exocrine pancreas. We aimed to evaluate telocytes presence in parotid stroma and whether their topographical features might support an involvement in parotid function modulation. Serial ultrathin sections of human and rat parotid glands were studied and compared by transmission electron microscopy. Two‐dimensional concatenation of sequenced micrographs allowed the ultrastructural identification of parotid telocytes, with their specific long, thin, and moniliform prolongations (telopodes). Telocyte location appeared frequently as a strategic one, in close contact or vicinity of both secretory (acini and ducts) and regulatory (nerves and blood vessels) apparatuses. They were also found in the interacinar and the subductal stroma. Two previously reported telocyte markers (c‐kit/CD117 and vimentin) were assayed by immunohistochemistry. Actin expression was also evaluated. Telocytes are making a network, especially by branching of their long telopodes. Elements of this telocyte network are interacting with each other (homocellular connections) as well as with other cell types (heterocellular connections). These interactions are achieved either by direct contact (stromal synapse), or mediated via shed microvesicles/exosomes. Since telocyte connections include both neurovascular and exocrine elements (e.g., acini and ducts), it is attractive to think that telocytes might mediate and integrate neural and/or vascular input with parotid function. Anat Rec, 2012. © 2011 Wiley Periodicals, Inc.
One‐pot Chemoenzymatic Synthesis of Chiral 1,3‐Diols Using an Enantioselective Aldol Reaction with Chiral Zn2+ Complex Catalysts and Enzymatic Reduction Using Oxidoreductases with Cofactor Regeneration
Authors: Sonoike Shotaro , Itakura Toshinari , Kitamura Masanori , Aoki Shin 
Published: December 2011

AbstractWe previously reported on enantioselective aldol reactions of acetone and some aldehydes catalyzed by chiral Zn2+ complexes of L‐prolyl‐pendant [12]aneN4 (L‐ZnL1) and L‐valyl‐pendant [12]aneN4 (L‐ZnL2) in aqueous solution. Here, we report on the one‐pot chemoenzymatic synthesis of chiral 1,3‐diols in an aqueous solvent system at room temperature by a combination of enantioselective aldol reactions catalyzed by Zn2+ complexes of L‐ and D‐phenylalanyl‐pendant [12]aneN4 (L‐ZnL3 and D‐ZnL3) and the successive enantioselective reduction of the aldol products using oxidoreductases with the regeneration of the NADH (reduced form of nicotinamine adenine dinucleotide) cofactor. The findings indicate that all four stereoisomers of 1,3‐diols can be produced by appropriate selection of a chiral Zn2+‐complex and an oxidoreductase commercially available from the “Chiralscreen OH” kit.
Activated Carbon Preparation from Lignin by H3PO4 Activation and Its Application to Gas Separation
Authors: Sun Y. , Yang G. , Zhang J. , Wang Y. , Yao M. 
Published: December 2011

AbstractActivated carbons were produced from corn straw lignin using H3PO4 as activating agent. The optimal activation temperature for producing the largest BET specific surface area and pore volume of carbon was 500 °C. The maximum BET specific surface area and pore volume of the resulting carbon were 820 m2g–1 and 0.8 cm3g–1, respectively. The adsorption isotherm model based on the Toth equation together with the Peng‐Robinson equation of state for the determination of gas phase fugacity provide a satisfactory representation of high pressure CO2, CH4 and N2 adsorption. The kinetic adsorption results show that the breakthrough difference between CO2 and CH4 is not obvious, indicating that its kinetic separation performance is limited.
Influence of the Nucleobase and Anchimeric Assistance of the Carboxyl Acid Groups in the Hydrolysis of Amino Acid Nucleoside Phosphoramidates
Authors: Maiti Munmun , Michielssens Servaas , Dyubankova Natalia , Maiti Mohitosh , Lescrinier Eveline , Ceulemans Arnout , Herdewijn Piet 
Published: December 2011

AbstractNucleoside phosphoramidates (NPs) are a class of nucleotide analogues that has been developed as potential antiviral/antitumor prodrugs. Recently, we have shown that some amino acid nucleoside phosphoramidates (aaNPs) can act as substrates for viral polymerases like HIV‐1 RT. Herein, we report the synthesis and hydrolysis of a series of new aaNPs, containing either natural or modified nucleobases to define the basis for their differential reactivity. Aqueous stability, kinetics, and hydrolysis pathways were studied by NMR spectroscopy at different solution pD values (5–7) and temperatures. It was observed that the kinetics and mechanism (PN and/or PO bond cleavage) of the hydrolysis reaction largely depend on the nature of the nucleobase and amino acid moieties. Aspartyl NPs were found to be more reactive than Gly or β‐Ala NPs. For aspartyl NPs, the order of reactivity of the nucleobase was 1‐deazaadenine>7‐deazaadenine>adenine>thymine≥3‐deazaadenine. Notably, neutral aqueous solutions of Asp‐1‐deaza‐dAMP degraded spontaneously even at 4 °C through exclusive PO bond hydrolysis (a 50‐fold reactivity difference for Asp‐1‐deaza‐dAMP vs. Asp‐3‐deaza‐dAMP at pD 5 and 70 °C). Conformational studies by NMR spectroscopy and molecular modeling suggest the involvement of the protonated N3 atom in adenine and 1‐ and 7‐deazaadenine in the intramolecular catalysis of the hydrolysis reaction through the rare syn conformation.
ChemInform Abstract: SrP3N5O: A Highly Condensed Layer Phosphate Structure Solved from a Nanocrystal by Automated Electron Diffraction Tomography.
Authors: Sedlmaier Stefan J. , Mugnaioli Enrico , Oeckler Oliver , Kolb Ute , Schnick Wolfgang 
Published: December 2011

AbstractThe title compound is synthesized from a mixture of SrS, OP(NH2)3, SP(NH2)3, and NH4Cl (silica glass ampule, 750 °C, 72 h).
ChemInform Abstract: Magnetic Properties of New Compounds RuMn2Sn and RuMn2Si.
Authors: Endo K. , Kanomata T. , Nishihara H. , Ziebeck K. R. A. 
Published: December 2011

AbstractThe title compounds are prepared from the elements (1000—1100 °C, 6—9 d) and characterized by powder XRD and magnetic measurements.
ChemInform Abstract: Synthesis, Crystal Structures, and Optical Properties of NaCdPnS3 (Pn: As, Sb).
Authors: Wu Yuandong , Bensch Wolfgang 
Published: December 2011

AbstractNaCdAsS3 (I) and NaCdSbS3 (II) are prepared by reaction of a mixture of Cd, Na2S, As2S3 or Sb, and S powder in 1:2:1:4 and 1:1:1:8 molar ratios, respectively (500 °C, 4 d; 70% and 50% yield for (I) and (II), respectively).
ChemInform Abstract: Synthesis and Crystal Structure of [Li8(H2O)29] [Sn10O4S20]·2H2O.
Authors: Kaib Thomas , Kapitein Manuel , Dehnen Stefanie 
Published: December 2011

AbstractThe title compound is obtained in the attempt to prepare the tetrameric [Sn4S10]4‐ anion by acidification of an aqueous solution of Li4[SnS4] with HCl followed by slow evaporation of the solvent (pH 7 , argon stream, 80 °C; 11% yield).
ChemInform Abstract: Sr3[Co(CN)3] and Ba3[Co(CN)3]: Crystal Structure, Chemical Bonding, and Conceptional Considerations of Highly Reduced Metalates.
Authors: Hoehn Peter , Jach Franziska , Karabiyik Baris , Prots Yurii , Agrestini Stefano , Wagner Frank R. , Ruck Michael , Tjeng Liu Hao , Kniep Ruediger 
Published: December 2011

AbstractThe title compounds are obtained from mixtures of Sr2N or Ba2N, Co, and NaCN (Ta ampule, Ar, 1223 K, 25 h).
ChemInform Abstract: Lewis Acid Mediated Acetal Substitution Reactions: Mechanism and Application to Asymmetric Catalysis.
Authors: Kobayashi Shu , Arai Kenzo , Yamakawa Takeshi , Chen Yi‐Jing , Salter Matthew M. , Yamashita Yasuhiro 
Published: December 2011

AbstractThe substitution of acetals with carbon nucleophiles is studied.
ChemInform Abstract: exo‐Selective Asymmetric Diels—Alder Reaction of 2,4‐Dienals and Nitroalkenes by Trienamine Catalysis.
Authors: Jia Zhi‐Jun , Zhou Quan , Zhou Qing‐Qing , Chen Peng‐Qiao , Chen Ying‐Chun 
Published: December 2011

AbstractThe first asymmetric Diels—Alder cycloaddition of 2,4‐dienals with nitroalkenes is presented, catalyzed by an in situ generated trienamine catalyst.
ChemInform Abstract: Rapid and Selective Deallylation of Allyl Ethers and Esters Using Iodine in Polyethylene Glycol‐400.
Authors: Konda Shankaraiah G. , Humne Vivek T. , Lokhande Pradeep D. 
Published: December 2011

AbstractA simple and selective deallylation of aryl/alkyl ether and esters, which includes an easy work‐up and a readily available and inexpensive catalyst, is presented.
ChemInform Abstract: Efficient Asymmetric Copper(I)‐Catalyzed Henry Reaction Using Chiral N‐Alkyl‐C1‐tetrahydro‐1,1′‐bisisoquinolines.
Authors: Ji Yao Qiong , Qi Gao , Judeh Zaher M. A. 
Published: December 2011

AbstractA new catalyst system is used in the enantioselective reaction of various (hetero)aromatic and aliphatic aldehydes with nitroalkanes.
ChemInform Abstract: Nanoceria‐Catalyzed Ullmann‐type Coupling Reactions.
Authors: Agawane Sandeep M. , Nagarkar Jayashree M. 
Published: December 2011

AbstractReactive halobenzenes such as (II) and (IV) are found to optimal for the process, which allows the synthesis of various phenol ethers and amines as well as that of thioether (X).
ChemInform Abstract: An Efficient Synthesis of Rubin′s Aldehyde and Its Precursor 1,3,5‐Tribromo‐2,4,6‐tris(dichloromethyl)benzene.
Authors: Holst Christoph , Schollmeyer Dieter , Meier Herbert 
Published: December 2011

AbstractThe title compound (IV) serves as precursor of hexaethynylbenzenes and other [6]star compounds.
ChemInform Abstract: A New Organic Transformation by Introducing Crotyl/Allyltrifluoroborates in Cross‐Coupling Reaction with Aroyl Chlorides.
Authors: Al‐Masum Mohammad , Liu Kwei‐Yu 
Published: December 2011

AbstractWith allyltrifluoroborate β‐adducts are obtained, whereas crotyltrifluoroborate yields α‐adducts selectively.
ChemInform Abstract: Palladium‐Catalyzed Direct C—H Arylation of Unactivated Arenes with Aryl Halides.
Authors: Hong WenKun , Qiu Yatao , Yao Zhiyi , Wang Zhaoyang , Jiang Sheng 
Published: December 2011

AbstractAn unprecedented oxidative coupling of aryl iodides and bromides with unactivated arenes to yield either symmetrical or unsymmetrical biaryls is possible under conditions A) at different temperatures.
ChemInform Abstract: CuCl/Bipyridine‐Catalyzed Addition Reactions of Arylboroxines with Aldehydes, α,β‐Unsaturated Ketones, and N‐Tosyl Aldimines.
Authors: Liao Yuan‐Xi , Hu Qiao‐Sheng 
Published: December 2011

AbstractThe process affords various benzylic alcohols, β‐arylated ketones, and diarylmethylamines.
ChemInform Abstract: New Three‐Component Condensation Reaction: Synthesis of 1‐[(Alkylthio)(phenyl)methyl]‐naphthalene‐2‐ol Catalyzed by Bromodimethylsulfonium Bromide (BDMS).
Authors: Khan Abu T. , Ali Shahzad , Dar Ajaz A. , Lal Mohan 
Published: December 2011

AbstractThe simple process including an inexpensive catalyst allows the preparation of various target compounds which may be of biological interest.
ChemInform Abstract: Custom Synthesis of Substituted Butenolides, Dihydropyranones, and α‐(E)‐Alkylidenelactones via Alkenylalumination.
Authors: Ramachandran P. Veeraraghavan , Pratihar Debarshi , Garner Garrett , Raju B. China 
Published: December 2011

AbstractStarting from aldehydes (II), the synthesis of butenolide and dihydropyranone structures is achieved by alkenylalumination, O‐protection and lactamization.
ChemInform Abstract: Functionalization of the 3‐Position of Thiophene and Benzo[b]thiophene Moieties by Palladium‐Catalyzed C—C Bond Forming Reactions Using Diazonium Salts.
Authors: Raduan Monica , Padrosa Joaquim , Pla‐Quintana Anna , Parella Teodor , Roglans Anna 
Published: December 2011

AbstractThe Matsuda—Heck reactions and Suzuki—Miyaura cross‐couplings are performed without ligand and base at room temperature, under aerobic conditions and in short reaction times.
ChemInform Abstract: Unprecedented C‐2 Arylation of Indole with Diazonium Salts: Syntheses of 2,3‐Disubstituted Indoles and their Antimicrobial Activity.
Authors: Magedov Igor V. , et al. et al. 
Published: December 2011

AbstractThe unprecedented reaction of indole (I) with an excess of aryldiazonium salts (II) provides access to 2‐aryl‐3‐(arylazo)indoles (III).
ChemInform Abstract: Co/Mn‐Mediated Oxidative Cross‐Coupling of Indoles with β‐Keto Esters via Dioxygen Activation: An Efficient Access to Ketonization—Olefination of Indoles.
Authors: Wu Wenliang , Xu Jing , Huang Shijun , Su Weiping 
Published: December 2011

AbstractThe title reaction proceeds under mild conditions yielding highly functionalyzed indoles with excellent selectivity in high yields.
ChemInform Abstract: Gold‐ or Palladium‐Catalyzed Allene Carbocyclization/Functionalization: Simple and Efficient Synthesis of Carbazoles.
Authors: Alcaide Benito , Almendros Pedro , Alonso Jose M. , Quiros M. Teresa , Gadzinski Pawel 
Published: December 2011

AbstractCarbazole derivatives are easily prepared from indole‐tethered allenols under mild conditions.
ChemInform Abstract: Azomethine Ylide Mediated Inversion of Configuration of Quaternary Imidazoline Carbon: Converting trans‐ to Its cis‐Imidazolines.
Authors: Qu Ke , Fisk Jason S. , Tepe Jetze J. 
Published: December 2011

AbstractReaction of trans‐4,5‐diaryl‐2‐imidazolines with aliphatic and aromatic aldehydes is accompanied by decarboxylation to yield cis‐4,5‐diaryl‐2‐imidazolines (III) after oxidation of the intermediate alcohols.
ChemInform Abstract: Trifluoromethylation of Aromatic Isoxazoles: Regio‐ and Diastereoselective Route to 5‐Trifluoromethyl‐2‐isoxazolines.
Authors: Kawai Hiroyuki , Tachi Kentaro , Tokunaga Etsuko , Shiro Motoo , Shibata Norio 
Published: December 2011

AbstractThe activation of aromatic, heteroaromatic, or styryl isoxazoles such as (I) or (V) with a nitro group at the 4‐position results in the first diastereoselective trifluoromethylation at the 5‐position by nucleophilic addition of Tms‐CF3.
ChemInform Abstract: Synthesis of Some Novel Triazole Derivatives and Investigation of their Antimicrobial Activities.
Authors: Altintop Mehlika Dilek , Kaplancikli Zafer Asim , Turan‐Zitouni Guelhan , Oezdemir Ahmet , Demirci Fatih , Iscan Goekalp , Revial Gilbert 
Published: December 2011

AbstractCompounds (IIIe) and (IIIf) are found to be the most potent derivatives against Candida species and tested bacteria, respectively.
ChemInform Abstract: Zn(Proline)2: A Novel Catalyst for the Synthesis of Dicoumarols.
Authors: Siddiqui Zeba N. , Farooq Farheen 
Published: December 2011

AbstractHydroxycoumarin (I) and aromatic aldehydes undergo the Zn‐catalyzed reaction in water to give the desired (arylmethylene)dicoumarols in <90% yield within minutes.
ChemInform Abstract: Synthesis of Dihydrochromeno[4,3‐b]pyrrolo[3,2‐f]quinolines via Intramolecular Aza Diels—Alder Reaction.
Authors: Ramesh Subburethinam , Nagarajan Rajagopal 
Published: December 2011

AbstractThe direct one‐pot process includes imine formation followed by Cu‐catalyzed intramolecular Diels—Alder cycloaddition.