- Controlled hydrogenation of diphenylacetylene using alkylammonium formate
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A simple and straightforward semihydrogenation of alkyne to alkene with triethanolamine and formic acid in the presence of PdCl2 has been described. Although hydrogenation using formic acid as a hydrogenation source has been used in combination with amines previously, few reports are available concerning the associated reactivity. We demonstrated that reactivity changes depending on the type of amine used in the hydrogenation. Further, this reaction requires no strict time control, making it a useful tool in organic synthesis.
- Suzuki, Hideyuki,Satoh, Ikkyu,Nishioka, Hiromi,Takeuchi, Yasuo
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supporting information
p. 3834 - 3837
(2017/09/15)
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- Cyclopropanation of olefins with diazo compounds catalyzed by a dicopper-substituted silicotungstate [γ-H2SiW 10O36Cu2(μ-1,1-N3) 2]4-
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The dicopper-substituted γ-Keggin silicotungstate (TBA) 4[γ-H2SiW10O36Cu 2II(μ-1,1-N3)2] (I, TBA = tetra-n-butylammonium) could act as an efficient precatalyst for the chemoselective cylopropanation of olefins with diazo compounds. Various kinds of olefins were efficiently converted to the corresponding cyclopropane derivatives in good yields.
- Kamata, Keigo,Kimura, Toshihiro,Mizuno, Noritaka
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supporting information; experimental part
p. 702 - 703
(2011/01/08)
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- Cross-metathesis assisted by microwave irradiation
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Microwave irradiation effectively accelerates cross-coupling metathesis reactions between deactivated olefins. Reactions have been carried out with the phosphine-free Hoveyda-Grubbs catalyst and the "second generation Grubbs' catalyst." While there have been reports that a "microwave effect" is observed in various transformations, the accelerations we observe are due to the efficient and rapid heating and increased pressure in the microwave apparatus.
- Bargiggia, Frederic C.,Murray, William V.
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p. 9636 - 9639
(2007/10/03)
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- Rhodium(II)-mediated reactions of thiobenzoylketene S,N-acetals with α-diazo carbonyl compounds: Synthesis of 2-substituted 3-alkylamino-5-phenylthiophenes
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Treatment of 3-methylamino-3-methylsulfanyl-1-phenylpropenethione 1 with excess (2.5 equiv.) α-diazo carbonyl compounds such as α-diazoketones and α-diazoesters in the presence of a catalytic amount of Rh(II) acetate in CH2Cl2 at rt gave 2-acyl- or 2-aroyl-3-methylamino-5-phenylthiophenes and alkyl 3-methylamino-5-phenylthiophene-2-carboxylates, respectively, as major products along with 1-phenyl-2-methylsulfanylethanones. The formation of the major products indicates that the carbenes or carbenoids generated interact initially with the thione sulfur of 1.
- Song, Hyun Min,Kim, Kyongtae
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p. 2414 - 2417
(2007/10/03)
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- Polyalkylation of 2,2-bis(hydroxymethyl)-1-alkanols with tert-butyl bromoacetate
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A series of 2,2-bis(hydroxymethyl)-1-alkanols was poly-O-alkylated in satisfactory yields with the tert-butyl bromoacetate by phase transfer catalysis. The resulting pure polyesters were converted in polyacids in quantitative yields.
- Dupuy,Viguier,Dupraz
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p. 1307 - 1313
(2007/10/03)
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- Concave reagents 32: Syn- and anti-selective cyclopropanation of alkenes with diazoacetates catalyzed by copper(I) complexes of concave 1,10- phenanthrolines
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Two classes of concave 1,10-phenanthroline ligands 1 and 2 have been used in the copper(I) catalyzed cyclopropanation of several acyclic and cyclic alkenes 3 with three diazoacetates 4-6. The bimacrocyclic 2,9-diaryl- 1,10-phenanthrolines 1 favor the anti(trans- or exo-) cyclopropanation with anti/syn-selectivities of up to > 99:1 (8g). In contrast, with the 1,10- phenanthroline bridged calix[6]arenes 2 as ligands a rarely observed syn- selective cyclopropanation was achieved. Methyl diazoacetate (6) showed the best syn-selectivities with anti/syn-ratios of up to 14:86 (9g).
- L?ffler, Frank,Hagen, Martin,Lüning, Ulrich
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p. 1826 - 1828
(2007/10/03)
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- Highly cis- and enantioface-selective cyclpropanation using (R,R)-Ru- salen complex: Solubility dependent enantioface selection
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The reaction of styrene and t-butyl α-diazoacetate in the presence of (R,R)-(ON+)(salen)ruthenium(II) complex 1 under the irradiation of incandescent light in THF gave the corresponding (IS,2R)- cyclopropanecarboxylate with high stereoselectivi
- Uchida, Tatsuya,Irie, Ryo,Katsuki, Tsutomu
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p. 1793 - 1795
(2007/10/03)
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- Ruthenium(II)Cl2-Bis(oxazolinyl)bipyridine Complex. Its Structure and Reactivity
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A mixture of 2 and 6,6'-bis(oxazolinyl)-2,2'-bipyridine (Bipymox-ip) was heated in ethanol at 70 deg C to produce Ru(II)Cl2(Bipymox-ip), of which structure was clarified by X-ray analysis to show that Bipymox-ip binds as a tetradentate ligand.Its catalytic activities for transformations of diazoacetates in dimerization and cyclopropanation with styrene were examined and its spectroelectrochemistry was studied.
- Nishiyama, Hisao,Park, Soon-Bong,Haga, Masa-aki,Aoki, Katsuyuki,Itoh, Kenji
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p. 1111 - 1114
(2007/10/02)
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- Generation and Reactions of Novel Copper Carbenoids through a Stoichiometric Reaction of Copper Metal with gem-Dichlorides in Dimethyl Sulfoxide
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Copper metal and such gem-dichlorides as α,α-dichloro acid esters, 1a-e, diphenyldichloromethane, 2, benzal chloride, 3, 1,1-dichloro-2-butene, 5, and carbon tetrachloride, 6, were found to produce copper carbenoid intermediates via α,α-elimination of dichlorides along with the formation of CuCl2(DMSO)2.Thus, 1 and 2 gave substituted olefins via a carbenoid coupling reaction.From 5 and 6, reaction products via the oxygen abstraction from DMSO were produced together with dimethyl sulfide; 3 and 4 were found to cause both types of reactions.The carbenoid intermediates formed from 1 did not cause cyclopropanation reaction with cyclohexene in contrast to the conventional carbalkoxy carbenoid generated by a decomposition reaction of ethyl diazoacetate.Also the carbenoid coupling reaction was completely inhibited by the addition of triphenylphosphine, which was contrastive to the formation of phosphonium ylide with a carbenoid from ethyl diazoacetate.
- Tezuka, Yasuyuki,Hashimoto, Akio,Ushizaka, Koh,Imai, Kiyokazu
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p. 329 - 333
(2007/10/02)
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- Semicorrin Metal Complexes as Enantioselective Catalysts. Part 2. Enantioselective Cyclopropane Formation from Olefins with Diazo Compounds Catalyzed by Chiral (Semicorrinato)copper Complexes)
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Copper complexes of chiral, C2-symmetric semicorrin ligands were found to be efficient catalysts for the cyclopropane formation from olefins with diazo compounds.In the presence of 1 mol-percent of catalyst, alkyl diazoacetates reacted smoothly with termi
- Fritschi, Hugo,Leutenegger, Urs,Pfaltz, Andreas
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p. 1553 - 1565
(2007/10/02)
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