- 1-Naphthyltropylium Ions Having Condensed Aromatic Rings at the 8-Position: Dependence of the Intramolecular Charge-Transfer Interaction upon Gemetry of the Donor
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A series of 1-aryl-8-tropylionaphthalene cations (aryl = 1-naphthyl (8a), 2-naphthyl (8b), 1-pyrenyl (8c), and 2-pyrenyl (8d) have been synthesized, in which the condensed aromatic system and a tropylium ring are placed at a face-to-face arrangement.The 1H NMR spectra of these cations exhibit remarkable upfield shift for the tropylium ring protons in accord with such molecular geometry; this geometry is further supported by theoretical calculations both by MMP2 and by AM1.The cations 8a-d show the intramolecular charge-transfer (CT) band at 510 (sh) (8a), 525 (sh) (8b), 585 (8c), and 600 (sh) nm (8d) in dichloromethane, indiacting a correlation of the CT transition energy with the donor's ionzation potential regardless of the relative geometry with the acceptor.In contrast, the indicies of cation's thermodynamic stability, pKR+ (6.27 for 8a, 5.45 for 8b, 6.28 for 8c, and 5.75 for 8d), and reduction potential (-0.649 V vs Ag/Ag+ for 8a, -0.601 for 8b, -0.665 for 8c, and -0.625 V for 8d) are highly dependent on the mutual geometry of donor and acceptor, reflecting the effectiveness in overlap of donor's HOMO and acceptor's LUMO.
- Tsuji, Ryotaro,Komatsu, Koichi,Inoue, Yoichiro,Takeuchi, Ken'ichi
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Read Online
- Enantioselective α-Arylation of Ketones via a Novel Cu(I)-Bis(phosphine) Dioxide Catalytic System
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A novel catalytic system based on copper(I) and chiral bis(phosphine) dioxides is described. This allows the arylation of silyl enol ethers to access enolizable α-arylated ketones in good yields and enantiomeric excess up to 95%. Noncyclic ketones are amenable substrates with this method, which complements other approaches based on palladium catalysis. Optimization of the ligand structure is accomplished via rational design driven by correlation analysis. Preliminary mechanistic hypotheses are also evaluated in order to identify the role of chiral bis(phosphine) dioxides.
- Escudero-Casao, Margarita,Licini, Giulia,Orlandi, Manuel
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supporting information
p. 3289 - 3294
(2021/04/07)
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- Stereodivergent Construction of Vicinal Acyclic Quaternary-Tertiary Carbon Stereocenters by Michael-Type Alkylation of α,α-Disubstituted N- tert-Butanesulfinyl Ketimines
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Vicinal quaternary-tertiary carbon stereocenters were constructed with excellent stereoselectivity via aza-enolization of enantioenriched acyclic N-tert-butanesulfinyl ketimines bearing two sterically similar α-linear alkyl substituents followed by conjugate addition to nitroalkenes. Further changes of the absolute configuration of the sulfinyl group and/or the α-stereocenter in the ketimine allowed the facile stereodivergent synthesis of all four diastereomers of the Michael-type alkylation adducts. This reaction is a successful example of acyclic stereocontrol based on stereoselective α-deprotonation for the formation of fully substituted aza-enolates from ketone derivatives.
- Liu, Hui,Lu, Chong-Dao,Yao, Yun,Yisimayili, Nuermaimaiti
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supporting information
p. 7450 - 7455
(2021/10/02)
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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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- Bismuth-catalyzed synthesis of polycyclic aromatic hydrocarbons (PAHs) with a phenanthrene backbone via cyclization and aromatization of 2-(2-arylphenyl)vinyl ethers
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The reaction of 2-(2-arylphenyl)vinyl ethers in the presence of a catalytic amount of bismuth(III) triflate gave substituted phenanthrenes in excellent yields under mild reaction conditions. The reaction was also applied to the construction of other polycyclic aromatic hydrocarbons (PAHs), such as chrysene, helicene, and pyrene having a phenanthrene backbone, via regioselective cyclization. This method has the advantages of easy availability of the cyclization precursors, operational simplicity, and high reaction efficiency.
- Murai, Masahito,Hosokawa, Naoki,Roy, David,Takai, Kazuhiko
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supporting information
p. 4134 - 4137
(2014/09/30)
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- Synthesis and optical properties of dithienostiboles
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Dithienostiboles having a stibole ring fused with a bithiophene system were prepared by the reactions of β,β'-dilithiobithiophene derivatives with aryldichlorostibines. Their optical properties were examined with respect to the UV absorption and emission spectra. DFT calculations on a model were also carried out to understand the electronic states.
- Ohshita, Joji,Fujita, Risa,Tanaka, Daiki,Ooyama, Yousuke,Kobayashi, Norifumi,Higashimura, Hideyuki,Yamamoto, Yohsuke
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supporting information
p. 1002 - 1003
(2012/10/29)
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- Cross-coupling of aryl/alkenyl silyl ethers with grignard reagents through nickel-catalyzed CO bond activation
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CO activation and its application have drawn much attention since oxygen-based electrophiles are easily available, less toxic, and more environmentally benign. This letter presents systematically results on the Ni-catalyzed KumadaTamaoCorriu coupling based on siloxy arenes/alkenes, which provides a new strategy of silyl protection/CC bond formation sequence in organic synthesis.
- Zhao, Fei,Yu, Da-Gang,Zhu, Ru-Yi,Xi, Zhenfeng,Shi, Zhang-Jie
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supporting information; experimental part
p. 1001 - 1003
(2011/12/05)
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- Phenanthroline derivative compound
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The present invention provides a novel phenanthroline derivative compound, and a manufacturing method thereof, and an electron transporting material, a light emitting element, a light emitting device, and an electronic device using the phenanthroline derivative compound. The phenanthroline derivative compound is characterized by being represented by General Formula 1. Note in General Formula 1 that Ar1 represents an aryl group, and preferably a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted anthryl group, or a substituted or unsubstituted phenanthryl group. As an example of a preferable compound, there is TMPBP, NaBP, PBP, or the like. A light emitting element, a light emitting device, and an electronic device preferably contain the compound in a light emitting layer, and in that case, the compound is preferably utilized as a host.
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Page/Page column 15
(2008/06/13)
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