1577-18-0Relevant articles and documents
Stereoselective catalytic hydrogenation of sorbic acid and sorbic alcohol with new Cp*Ru complexes
Steines, Stephan,Englert, Ulli,Driessen-Hoelscher, Birgit
, p. 217 - 218 (2000)
The new Cp*Ru complexes [Cp*Ru(η4-MeCH=CHCH=CHCO2H)]+X- (X- = CF3SO3- or [B{C6H3(CF3)2-3,5}4]-) are very effective catalysts for the hydrogenation of sorbic acid to cis-hex-3-enoic acid and of sorbic alcohol to cis-hex-3-en-1-ol (leaf alcohol) under mild conditions in liquid two-phase systems.
Rh2(R -TPCP)4-catalyzed enantioselective [3+2]-cycloaddition between nitrones and vinyldiazoacetates
Qin, Changming,Davies, Huw M. L.
, p. 14516 - 14519 (2013)
Rhodium-catalyzed reaction of vinyldiazoacetates with nitrones results in a formal [3+2]-cycloaddition to generate 2,5-dihydroisoxazoles with high levels of asymmetric induction. The cascade reaction begins with a vinylogous addition event, followed by an iminium addition ring-closure/hydride migration/alkene isomerization cascade. Dirhodium tetrakis(triarylcyclopropanecarboxylates) are the optimum catalysts for this process.
Palladium-Catalyzed Amide-Directed Enantioselective Hydrocarbofunctionalization of Unactivated Alkenes Using a Chiral Monodentate Oxazoline Ligand
Wang, Hao,Bai, Zibo,Jiao, Tangqian,Deng, Zhiqiang,Tong, Huarong,He, Gang,Peng, Qian,Chen, Gong
supporting information, p. 3542 - 3546 (2018/03/21)
A Pd-catalyzed amide-directed enantioselective hydrocarbofunctionalization of unactivated alkenes with C-H nucleophiles has been developed using a chiral monodentate oxazoline (MOXin) ligand. Various indoles react at C3 position with aminoquinoline-coupled 3-alkenamides to give γ addition products in good to excellent yield and enantioselectivity. This study represents an important advance of the development of chiral monodentate oxazoline ligands, which have been underexplored for asymmetric catalysis.
Characterization of an epoxide hydrolase from the Florida red tide dinoflagellate, Karenia brevis
Sun, Pengfei,Leeson, Cristian,Zhi, Xiaoduo,Leng, Fenfei,Pierce, Richard H.,Henry, Michael S.,Rein, Kathleen S.
, p. 11 - 21 (2016/02/03)
Epoxide hydrolases (EH, EC 3.3.2.3) have been proposed to be key enzymes in the biosynthesis of polyether (PE) ladder compounds such as the brevetoxins which are produced by the dinoflagellate Karenia brevis. These enzymes have the potential to catalyze kinetically disfavored endo-tet cyclization reactions. Data mining of K. brevis transcriptome libraries revealed two classes of epoxide hydrolases: microsomal and leukotriene A4 (LTA4) hydrolases. A microsomal EH was cloned and expressed for characterization. The enzyme is a monomeric protein with molecular weight 44 kDa. Kinetic parameters were evaluated using a variety of epoxide substrates to assess substrate selectivity and enantioselectivity, as well as its potential to catalyze the critical endo-tet cyclization of epoxy alcohols. Monitoring of EH activity in high and low toxin producing cultures of K. brevis over a three week period showed consistently higher activity in the high toxin producing culture implicating the involvement of one or more EH in brevetoxin biosynthesis.
Regioselective ring opening and isomerization reactions of 3,4-epoxyesters catalyzed by boron trifluoride
Izquierdo, Javier,Rodriguez, Santiago,Gonzalez, Florenci V.
supporting information; experimental part, p. 3856 - 3859 (2011/09/19)
Efficient ring opening of 3,4-epoxyesters with alcohols to produce 4-alkoxy-3-hydroxyesters and their isomerization into 4-ketoesters using boron trifluoride as the catalyst are presented. Both transformations are simple and efficient methods for the synthesis of the above named synthetically useful compounds.
Method for regio- and stereoselective synthesis of (E)-Β,γ- unsaturated acids from aldehydes under solvent-free conditions
Zhang, Shi-Jie,Hu, Wei-Xiao
experimental part, p. 3093 - 3100 (2010/12/19)
Synthesis of (E)-β,-γunsaturated acids from aldehydes with malonic acid has been explored under solvent-free conditions. The modified Knoevenagel condensation reaction with N-methyl morpholine (NMM) as catalyst exhibits highly β,-γ regioselectivity and exclusively E-stereoselectivity. A mechanism accounting for both regio- and stereoselectivity has been proposed and preliminarily studied. Copyright Taylor & Francis Group, LLC.
General and practical conversion of aldehydes to homologated carboxylic acids
Cafiero, Lauren R.,Snowden, Timothy S.
supporting information; experimental part, p. 3853 - 3856 (2009/07/01)
(Chemical Equation Presented) The reaction of aldehydes with trichloromethide followed by sodium borohydride or sodium phenylseleno(triethyl) borate under basic conditions affords homologated carboxylic acids in high yields. This operationally simple procedure provides a practical, efficient alternative to other homologation protocols. The approach is compatible with sensitive aldehydes including enals and enolizable aldehydes. It also offers convenient access to α-monodeuterated carboxylic acids.
Process for preparing cis alkenes and new catalysts therefor
-
Page/Page column 9, (2010/02/05)
In a method for preparation of cis-alkenes (I) by hydrogenating conjugated, non-cyclic dienes (II) in presence of homogeneously soluble transition metal catalyst (III), the new feature is that (III) is prepared in situ. In a method for preparation of cis-alkenes (I) by hydrogenating conjugated, non-cyclic dienes (II) in presence of homogeneously soluble transition metal catalyst (III), the new feature is that (III) is prepared in situ. (III) are of formulae (IIIa) or (IIIb). M = in (IIIa), a transition metal of Group VI in zero oxidation state, or in (IIIb) a metal of Group VIII in +2 oxidation state, Group IX in +1 oxidation state or Group X in +2 oxidation state; L1 = polydentate neutral or anionic ligand; L2 and L3 = together a conjugated, non-cyclic diene ligand; L4 = monodentate neutral ligand; L5 = polydentate neutral ligand; X = anion; and n = 1 or 2. Independent claims are also included for the following: (1) transition metal complex (C) for stereoselective hydrogenation of conjugated dienes to cisoid compounds that comprises a central ruthenium(II), an eta5 ligand, a bidentate, non-cyclic conjugated diene ligand and optionally a non-coordinating counterion for electrical neutrality, provided that when the ligand is pentamethylcyclopentadienyl (CpMe5) and the diene is sorbic acid, then the counterion is not triflate (trifluoromethylsulfonate) nor the BARF anion; and (2) methods for preparing specific (C).
Stereoselective access to functionalized β-γ unsaturated acids
Thibonnet, Jér?me,Abarbri, Mohamed,Parrain, Jean-Luc,Duchêne, Alain
, p. 4433 - 4441 (2007/10/03)
Stereoselective synthesis of vinylstannanes bearing a carboxylic acid function was achieved from β-γ alkynoic acids via hydrostannation, stannylcupration or silastannation reactions. Regioselectivity is highly dependent on the nature of the stannylanions used and on protection of the carboxylic acid function.
Synthesis of different deuterated carboxylic acids from unsaturated acids promoted by samarium diiodide and D2O
Concellon, Jose M.,Rodriguez-Solla, Humberto
, p. 4493 - 4497 (2007/10/03)
An easy, and rapid reduction of the C=C bond of α,β-unsaturated acids by means of samarium diiodide in the presence of D2O provides an efficient method for synthesizing 2,3-dideuterio acids. Starting from alka-2,4-dienoic acids, (E)-α,δ-dideuterio-βγ-unsaturated acids are obtained, the new C=C bond being generated with complete diastereoselectivity. When H2O is used instead of D2O, saturated carboxylic acids and (E)-β,γ-unsaturated acids are isolated. A mechanism to explain each synthesis has been proposed.
