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441.
Sakaguchi S Mizuta T Furuwan M Kubo T Ishii Y 《Chemical communications (Cambridge, England)》2004,(14):1638-1639
The coupling of amines, aldehydes and trimethylsilylacetylene was found to be promoted in the presence of a catalytic amount of [IrCl(cod)]2; 1 : 1 : 1 or 1 : 2 : 2 coupling products were obtained by allowing primary amine to react with aldehyde and trimethylsilylacetylene. 相似文献
442.
A number of mono(imidazole)-ligated complexes of perchloro(meso-tetramesitylporphyrinato)iron(III), [Fe(TMP)L]ClO(4), have been prepared, and their spin states have been examined by (1)H NMR, (13)C NMR, and EPR spectroscopy as well as solution magnetic moments. All the complexes examined have shown a quantum mechanical spin admixed state of high and intermediate-spin (S = 5/2 and 3/2) states though the contribution of the S = 3/2 state varies depending on the nature of axial ligands. While the complex with extremely bulky 2-tert-butylimidazole (2-(t)()BuIm) has exhibited an essentially pure S = 5/2 state, the complex with electron-deficient 4,5-dichloroimidazole (4,5-Cl(2)Im) adopts an S = 3/2 state with 30% of the S = 5/2 spin admixture. On the basis of the (1)H and (13)C NMR results, we have concluded that the S = 3/2 contribution at ambient temperature increases according to the following order: 2-(t)BuIm < 2-(1-EtPr)Im < 2-MeIm 相似文献
443.
Catalytic reductive alkylation of secondary amine with aldehyde and silane by an iridium compound 总被引:1,自引:0,他引:1
[reaction: see text] An efficient methodology for the reductive alkylation of secondary amine with aldehyde and Et(3)SiH using an iridium complex as a catalyst has been developed. For example, treatment of dibutylamine with butyraldehyde and Et(3)SiH (a 1:1:1 molar amount of amine, aldehyde, and silane) in 1,4-dioxane at 75 degrees C under the influence of a catalytic amount of [IrCl(cod)](2) gave tributylamine in quantitative yield. In this reaction, no reduction of aldehyde took place. It was found that IrCl(3), which is a starting material for preparation of iridium complexes such as [IrCl(cod)](2), acts as an efficient catalyst for the present reductive alkylation of amine. In addition, a cheaper, easy-to-handle, and environmentally friendly reducing reagent such as polymethylhydrosiloxane (PMHS) in place of Et(3)SiH was also useful. Thus, a variety of secondary amines could be alkylated by allowing them to react with aldehydes and PMHS in the presence of an iridium catalyst to afford the corresponding tertiary amines in good to excellent yields. From the deuterium label experiments, it was revealed that silane and water, generated during the formation of enamine by the reaction of amine and aldehyde, seem to behave as a hydrogen source. The catalytic cycle was discussed. 相似文献
444.
Yutaro Sekimoto Hiroshige Yoshida Tomoya Hirota Yasushi Takano Eri Furuyama Satoshi Yamamoto Shuji Saito Hiroyuki Ozeki Junji Inatani Masatoshi Ohishi Apostle G. Cardiasmenos Samuel L. Hensel 《International Journal of Infrared and Millimeter Waves》1996,17(7):1263-1284
We measured atmospheric opacity at 220 GHz at the summit of Mt. Fuji (alt. 3776 m) about one year in order to explore a feasibility of submillimeter-wave astronomical observations. For this purpose, a 220 GHz radiometer system enclosed in a radome (51×51×62 cm3) has been developed. The 220 GHz opacity was lower than 0.06 for a significant fraction ( 45 %) of time from November 1994 to March 1995. Diurnal variation of the opacity at the summit of Mt. Fuji is so small that continuous observation at submillimeter-wave is possible through day and night. Yearly variation of the opacity is studied from water vapor pressure data measured at the weather station for the past 3 years. To prevent accumulation of ice and snow on the Gore-Tex membrane in the radome, the outer membrane was supplied with a thermal flux of 0.63 kW m–2 and the adjacent metal radome surfaces were supplied with a flux of 0.9 kW m–2. We evaluate from the 220 GHz transmission data that this heat flux is sufficient to keep the membrane on the radome free of ice and snow during 83 % of the time in 5 winter months. The summit of Mt. Fuji appears to be a promising site for submillimeter-wave observations. 相似文献
445.
Back Cover: Synthesis and Applications of (ONO Pincer)Ruthenium‐Complex‐Bound Norvalines (Chem. Asian J. 7/2016)
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446.
A palladium(0)/monophosphine catalyst promotes a cyclization reaction of 2-(alkynyl)aryl isocyanates with organoboron reagents to produce stereodefined 3-alkylideneoxindoles. The alkynyl and isocyanato groups undergo oxidative cyclization with Pd(0) to form an oxapalladacycle intermediate. Subsequent transmetalation and reductive elimination afford the product. 相似文献
447.
Masahiko Shimada Tatsuro Harumashi Tomoya Miura Dr. Masahiro Murakami Prof. Dr. 《化学:亚洲杂志》2008,3(6):1035-1040
Methoxy‐substituted 1,6‐enynes react with arylboronic acids in the presence of a rhodium(I) complex to give arylated cyclization products. This occurs by a multi‐step mechanism consisting of rhodium/boron transmetalation, intermolecular carborhodation, intramolecular carborhodation, β‐hydride elimination, hydrorhodation, and β‐oxygen elimination. A shift of the position of a carbon–carbon double bond is observed, suggesting that the β‐hydride elimination/hydrorhodation process is repeatedly taking place. 相似文献
448.
Miura T Ueda K Takahashi Y Murakami M 《Chemical communications (Cambridge, England)》2008,(42):5366-5368
Allenynes having malonate-based tethers reacted with arylboronic acids in the presence of a rhodium(I) catalyst to sequentially form three carbon-carbon bonds, and arylated bicyclic skeletons were constructed in a stereoselective manner. 相似文献
449.
Dr. Tomoki Yoshida Masaya Ohta Tomoya Emmei Dr. Takuya Kodama Prof. Dr. Mamoru Tobisu 《Angewandte Chemie (International ed. in English)》2023,62(23):e202303657
The C−F bond of acyl fluorides can be cleaved and added across tethered alkenes in the presence of a cationic rhodium(I) tetrafluoroborate catalyst. This 1,2-carbofluorination reaction offers a powerful method for the synthesis of tertiary alkyl fluoride derivatives with an atom economy of 100 %. Mechanistic studies indicate that the concerted action of a rhodium cation and a tetrafluoroborate anion is key for the success of this catalytic cleavage and formation of C−F bonds in a controlled manner. 相似文献
450.
Hiroshi Y. Yoshikawa Ryota Murai Syou Maki Tomoya Kitatani Shigeru Sugiyama Gen Sazaki Hiroaki Adachi Tsuyoshi Inoue Hiroyoshi Matsumura Kazufumi Takano Satoshi Murakami Takatomo Sasaki Yusuke Mori 《Applied Physics A: Materials Science & Processing》2008,93(4):911-915
We have investigated femtosecond laser-induced nucleation of hen egg-white lysozyme (HEWL) as a function of the laser pulse
energy and pulse time width. This is the first recorded study to confirm that the femtosecond laser-induced nucleation of
HEWL can be induced at a specific threshold laser energy. The threshold energy is comparable to that of cavitation bubble
generation. The results strongly suggest that morphological changes in the solution are key factors for protein nucleation. 相似文献