4411-97-6Relevant articles and documents
Efficient one-to-one coupling of easily available 1,3-dienes with carbon dioxide
Takaya, Jun,Sasano, Kota,Iwasawa, Nobuharu
supporting information; experimental part, p. 1698 - 1701 (2011/05/04)
An efficient one-to-one coupling reaction of atmospheric pressure carbon dioxide with 1,3-dienes is realized for the first time through PSiP-pincer type palladium-catalyzed hydrocarboxylation. The reaction is applicable to various 1,3-dienes including easily available chemical feedstock such as 1,3-butadiene and isoprene. This protocol affords a highly useful method for the synthesis of β,γ-unsaturated carboxylic acid derivatives from CO2.
Two asymmetric syntheses of AMG 221, an inhibitor of 11β- hydroxysteroid dehydrogenase type 1
Caille, Seb,Cui, Sheng,Hwang, Tsang-Lin,Wang, Xiang,Faul, Margaret M.
experimental part, p. 3833 - 3842 (2009/11/30)
(Chemical Equation Presented) Two asymmetric syntheses of AMG 221 (2), an inhibitor of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) discovered in our laboratories, are reported. One of the syntheses utilizes chiral trimethylsilyl cyanohydrin 12 as s
Enantioselective Friedel-Crafts reactions of ethenetricarboxylates and substituted pyrroles and furans and intramolecular reaction of benzene derivatives
Yamazaki, Shoko,Kashima, Shinichi,Kuriyama, Taiki,Iwata, Yuko,Morimoto, Tsumoru,Kakiuchi, Kiyomi
experimental part, p. 1224 - 1234 (2009/10/24)
Compared to enantioselective Friedel-Crafts reactions of indoles, reactions of alkylidene malonates with monocyclic aromatic compounds generally proceed with low enantioselectivity. The Friedel-Crafts reactions of ethenetricarboxylates 1 and monocyclic heteroaromatic compounds, such as substituted pyrroles and furans were investigated. The reaction of 1 with 2,4-dimethylpyrrole in the presence of a chiral bisoxazoline-copper(II) complex (10 mol %) in tetrahydrofuran at room temperature gave alkylated products in up to 72% ee. The reaction of 1 with 2-substituted furans gave alkylated products in 46-62% ee. The absolute stereochemistry of the furan Friedel-Crafts product 7e was determined by transformation to the known 2,3-dimethylbutyric acid. The intramolecular reaction of benzene derivatives gave cyclized products up to 56% ee.
Synthesis of (-)-Vulcanolide by enantioselective protonation
Fehr, Charles,Chaptal-Gradoz, Nathalie,Galindo, Jose
, p. 853 - 858 (2007/10/03)
Two efficient enantioselective syntheses of the more active (S,S)-enantiomer of the powerful musk odorant Vulcanolide are described. In both syntheses, the key step is an enantioselective protonation of a ketone enolate. A third enantioselective protonati
Pyrrolidine modulators of chemokine receptor activity
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, (2008/06/13)
The present invention is directed to pyrrolidine compounds of the formula I: (wherein R1, R2, R3, R4, R5, R6, R14and n are defined herein) which are useful as modulators of chemokine receptor activity. In particular, these compounds are useful as modulators of the chemokine receptors CCR-5 and/or CCR-3.
Enantioselective hydrogenation of α,β-unsaturated acids. Substrate-modifier interaction over cinchonidine modified Pd/Al2O3
Borszeky,Mallat,Baiker
, p. 3745 - 3753 (2007/10/03)
X-Ray diffraction, IR measurements and catalytic hydrogenation of various substituted acrylic acids in apolar solvents, as well as molecular modelling provide new insight into the nature of the cinchonidine-substrate interaction and a general rule to predict the major enantiomer.
Highly efficient enantioselective synthesis of optically active carboxylic acids by Ru(OCOCH3)2[(S)-H8-BINAP]
Uemura, Toshitsugi,Zhang, Xiaoyoung,Matsumura, Kazuhiko,Sayo, Noboru,Kumobayashi, Hidenori,Ohta, Tetsuo,Nozaki, Kyoko,Takaya, Hidemasa
, p. 5510 - 5516 (2007/10/03)
In the presence of a catalytic amount of Ru(OCOCH3)2[(S)-H8-BINAP] [H8-BINAP = 2,2′-bis-(diphenylphosphino)-5,5′,6,6′,7,7′,8,8′- octahydro-1,1′-binaphthyl], the asymmetric hydrogenation of α,β- and β,γ-unsaturated carboxylic acids afforded the corresponding saturated carboxylic acids in higher enantiomeric excesses and at faster reaction rates than those using the Ru(OCOCH3)2[(R)-BINAP] catalyst [BINAP = 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl]. The hydrogenation of (E)-2-alkyl-2-alkenoic acids by the H8-BINAP catalyst system produced saturated acids in 95-97% ee. 2-Methylcinnamic acid was treated with H8-BINAP-Ru(II) complex as a catalyst to yield a hydrogenated product in much higher ee than that produced by BINAP-Ru(II) (89 and 30% ee, respectively). This homogeneous catalysis using H8-BINAP-Ru(II) established a promising synthetic route to (S)-ibuprofen in up to 97% ee. Asymmetric hydrogenation of β-disubstituted acrylic acids also proceeded smoothly with good enantioselectivities (70-93% ee). In addition, the hydrogenation of trisubstituted acrylic acids (up to 88% ee) was investigated. Hydrogen pressure effect on the sense and level of enantioselection was shown to be substrate dependent. The difference between the H8-BINAP- and BINAP-Ru(II) complexes was also discussed.
Preparation and Nitrosation of 3,4-Dimethyl-3-penten-2-one (E)- and (Z)-Oximes. Formation of 3,3,4,5-Tetramethyl-3H-pyrazole 1,2-Dioxide and of 2-Isoxazoline Derivatives
Hansen, John F.,Novak, Bennett H.
, p. 105 - 112 (2007/10/02)
The stereoisomeric (E)- and (Z)-oximes of 3,4-dimethyl-3-penten-2-one were prepared and nitrosated with butyl nitrite in methanol.The (E)-oxime gave 3,3,4,5-tetramethyl-3H-pyrazole 1,2-dioxide in nearly quantitative yield, while the (Z)-oxime reacted less readily, giving a lower yield of the same product, with five other products identified as isoxazoline derivatives.Three of these were 4-hydroxy-, 4-methoxy-, and 4-nitro-3,4,5,5-tetramethyl-2-isoxazoline.The fourth was the O-(3,4,5,5-tetramethyl--2-isoxazolin-4-yl) derivative of the starting (Z)-oxime, and the fifth was 4-methylene-3,5,5-trimethyl-2-isoxazoline.
A new synthetic route to methylenomycin B via Rhodium(II)-mediated decomposition of α,β-unsaturated α'-diazoketones
Ceccherelli,Curini,Marcotullio,Rosati
, p. 17 - 23 (2007/10/02)
A new synthesis of methylenomycin B, involving Rh(II)-catalyzed, intramolecular carbon-hydrogen insertion of diazoketone 2c, derived from 2,3-dimethyl-2-butenoic acid 2b, is reported.
The Gas-Flow Thermolysis of 1-Isobutenyl Alkynyl and 2-Methylphenyl Alkynyl Ketones. Synthesis of Methylenomycin B
Koller, Manuel,Karpf, Martin,Dreiding, Andre S.
, p. 560 - 579 (2007/10/02)
The gas-flow thermolysis of 1-isobutenyl alkynyl or 2-methyphenyl alkynyl ketones were found to lead to phenols and cyclopentenones or to naphthols and indanones, respectively.These conversions involve two cyclization processes so far unknown with α-alkynones; they are interpreted as intramolecular additions of an allylic or a benzylic C,H bond to a triple bond which may occur in two directions.In addition, the cyclopentenones formed by the α-alkynone cyclization, a known carbene process yielding 5-rings, were also found.The available evidence ruled out a carbene process yielding 6-rings.The addition process yielding 5-rings was applied to a short (but low yield) synthesis of methylenomycin B.
