17352-32-8Relevant articles and documents
Facile synthesis of (Z)-tetracos-5-enoic acid and racemic cis-4-(2-octadecylcyclopropane-1-yl)-butanoic acid
Coxon, Geoffrey D.,Douglas, James D.,Minnikin, David E.
, p. 49 - 53 (2003)
(Z)-Tetracos-5-enoic acid and racemic cis-4-(2-octadecylcyclopropane-1-yl)- butanoic acid have been prepared from 1-eicosene by a new facile route. Periodic acid cleavage of the epoxide of 1-eicosene gave nonadecanal which was condensed with 4-carboxybutyltriphenylphosphonium bromide to give predominately (Z)-tetracos-5-enoic acid. Simmons-Smith type cyclopropanation of (Z)-tetracos-5-enoic acid gave a minor proportion of racemic cis-4-(2-octadecylcyclopropane-1-yl)-butanoic acid accompanied by major amounts of its methyl ester.
Catalytic supercritical fluid extraction: Selective hydroformylation of olefin mixtures using scCO2 solubility for differentiation
Koch, Timo J.,Desset, Simon L.,Leitner, Walter
, p. 1719 - 1721 (2010)
A new reaction concept that allows one to control the substrate selectivity of a catalytic reaction by supercritical fluid extraction is demonstrated for the hydroformylation of long-chain olefins as a prototypical example.
Iron Catalyzed Hydroformylation of Alkenes under Mild Conditions: Evidence of an Fe(II) Catalyzed Process
Pandey, Swechchha,Raj, K. Vipin,Shinde, Dinesh R.,Vanka, Kumar,Kashyap, Varchaswal,Kurungot, Sreekumar,Vinod,Chikkali, Samir H.
supporting information, p. 4430 - 4439 (2018/04/05)
Earth abundant, first row transition metals offer a cheap and sustainable alternative to the rare and precious metals. However, utilization of first row metals in catalysis requires harsh reaction conditions, suffers from limited activity, and fails to tolerate functional groups. Reported here is a highly efficient iron catalyzed hydroformylation of alkenes under mild conditions. This protocol operates at 10-30 bar syngas pressure below 100 °C, utilizes readily available ligands, and applies to an array of olefins. Thus, the iron precursor [HFe(CO)4]-[Ph3PNPPh3]+ (1) in the presence of triphenyl phosphine catalyzes the hydroformylation of 1-hexene (S2), 1-octene (S1), 1-decene (S3), 1-dodecene (S4), 1-octadecene (S5), trimethoxy(vinyl)silane (S6), trimethyl(vinyl)silane (S7), cardanol (S8), 2,3-dihydrofuran (S9), allyl malonic acid (S10), styrene (S11), 4-methylstyrene (S12), 4-iBu-styrene (S13), 4-tBu-styrene (S14), 4-methoxy styrene (S15), 4-acetoxy styrene (S16), 4-bromo styrene (S17), 4-chloro styrene (S18), 4-vinylbenzonitrile (S19), 4-vinylbenzoic acid (S20), and allyl benzene (S21) to corresponding aldehydes in good to excellent yields. Both electron donating and electron withdrawing substituents could be tolerated and excellent conversions were obtained for S11-S20. Remarkably, the addition of 1 mol % acetic acid promotes the reaction to completion within 16-24 h. Detailed mechanistic investigations revealed in situ formation of an iron-dihydride complex [H2Fe(CO)2(PPh3)2] (A) as an active catalytic species. This finding was further supported by cyclic voltammetry investigations and intermediacy of an Fe(0)-Fe(II) species was established. Combined experimental and computational investigations support the existence of an iron-dihydride as the catalyst resting state, which then follows a Fe(II) based catalytic cycle to produce aldehyde.
Total Synthesis of Mycobacterium tuberculosis Dideoxymycobactin-838 and Stereoisomers: Diverse CD1a-Restricted T Cells Display a Common Hierarchy of Lipopeptide Recognition
Cheng, Janice M. H.,Liu, Ligong,Pellicci, Daniel G.,Reddiex, Scott J. J.,Cotton, Rachel N.,Cheng, Tan-Yun,Young, David C.,Van Rhijn, Ildiko,Moody, D. Branch,Rossjohn, Jamie,Fairlie, David P.,Godfrey, Dale I.,Williams, Spencer J.
, p. 1694 - 1701 (2017/02/10)
Mycobacterium tuberculosis produces dideoxymycobactin-838 (DDM-838), a lipopeptide that potently activates T cells upon binding to the MHC-like antigen-presenting molecule CD1a. M. tuberculosis produces DDM-838 in only trace amounts and a previous solid-phase synthesis provided sub-milligram quantities. We describe a high-yielding solution-phase synthesis of DDM-838 that features a Mitsunobu substitution that avoids yield-limiting epimerization at lysine during esterification, and amidation conditions that prevent double-bond isomerization of the Z-C20:1 acyl chain, and provides material with equivalent antigenicity to natural DDM-838. Isomers of DDM-838 that varied in stereochemistry at the central lysine and the C20:1 acyl chain were compared for their ability to be recognised by CD1a-restricted T cell receptors (TCRs). These TCRs, derived from unrelated human donors, exhibited a similar spectrum of reactivity towards the panel of DDM-838 isomers, highlighting the exquisite sensitivity of lipopeptide-reactive T cells for the natural DDM stereochemistry.
Tetronics/cyclodextrin-based hydrogels as catalyst-containing media for the hydroformylation of higher olefins
Chevry,Vanbésien,Menuel,Monflier,Hapiot
, p. 114 - 123 (2017/08/14)
The rhodium-catalyzed hydroformylation of alkenes has been investigated under biphasic conditions using combinations of α-cyclodextrin (α-CD) and poloxamines (Tetronics). Thermo-responsive hydrogels containing the Rh-catalyst are formed under well-defined conditions of concentration. Hydrogels consisting of the reverse-sequential Tetronic 90R4 prove to be more effective than those containing the conventional sequential Tetronic 701. The presence of α-CD is crucial to provoke the decantation of the multiphasic system once the reaction is complete. Optimized conditions (CO/H2 pressure, Rh-precursors, phosphanes, etc.) show that the catalytic system is especially applicable to the hydroformylation of terminal alkenes. The catalytic performance remains unchanged upon recycling as the hydrogel matrix prevents the oxidation of the phosphane.
Enzyme Activity by Design: An Artificial Rhodium Hydroformylase for Linear Aldehydes
Jarvis, Amanda G.,Obrecht, Lorenz,Deuss, Peter J.,Laan, Wouter,Gibson, Emma K.,Wells, Peter P.,Kamer, Paul C. J.
supporting information, p. 13596 - 13600 (2017/09/25)
Artificial metalloenzymes (ArMs) are hybrid catalysts that offer a unique opportunity to combine the superior performance of natural protein structures with the unnatural reactivity of transition-metal catalytic centers. Therefore, they provide the prospect of highly selective and active catalytic chemical conversions for which natural enzymes are unavailable. Herein, we show how by rationally combining robust site-specific phosphine bioconjugation methods and a lipid-binding protein (SCP-2L), an artificial rhodium hydroformylase was developed that displays remarkable activities and selectivities for the biphasic production of long-chain linear aldehydes under benign aqueous conditions. Overall, this study demonstrates that judiciously chosen protein-binding scaffolds can be adapted to obtain metalloenzymes that provide the reactivity of the introduced metal center combined with specifically intended product selectivity.
Water-soluble phosphane-substituted cyclodextrin as an effective bifunctional additive in hydroformylation of higher olefins
Leblond,Potier,Menuel,Bricout,Machut-Binkowski,Landy,Tilloy,Monflier,Hapiot
, p. 3823 - 3830 (2017/09/07)
In cyclodextrin (CD)-mediated aqueous biphasic catalysis, favoring contacts between the CD ("host"), the organic substrate ("guest") and the water-soluble catalyst is crucial for the reaction to proceed efficiently at the aqueous/organic interface. Grafting the catalyst onto the CD backbone thus appears as an attractive approach to favor the molecular recognition of the substrate and its subsequent catalytic conversion into products. In this context, a new water-soluble β-CD-based phosphane was synthesized and characterized by NMR, tensiometric and ITC measurements. The β-CD-based phosphane consisted of a 3,3′-disulfonatodiphenyl phosphane connected to the primary face of β-CD by a dimethyleneamino spacer. Intra- and intermolecular inclusion processes of one of the two sulfophenyl groups into the β-CD cavity were identified in water. However, the association constant (Ka) related to the β-CD/sulfophenyl group couple was low. Accordingly, the inclusion process was easily displaced upon coordination to rhodium complexes. The efficacy of the resulting Rh-complex coordinated by β-CD-based phosphanes was assessed in Rh-catalyzed hydroformylation of higher olefins. The catalytic system proved to be far more successful and efficient than a system consisting of supramolecularly interacting phosphanes and CDs. The catalytic activity was up to 30-fold higher while the chemo- and regioselectivities remain rather unchanged.
Synergetic effect of randomly methylated β-cyclodextrin and a supramolecular hydrogel in Rh-catalyzed hydroformylation of higher olefins
Potier, Jonathan,Menuel, Stephane,Monflier, Eric,Hapiot, Frederic
, p. 2342 - 2346 (2014/07/21)
A significant improvement in Rh-catalyzed hydroformylation of very hydrophobic alkenes was achieved using a biphasic catalytic system consisting of a substrate-containing organic phase and a catalyst-containing hydrogel phase [consisting of poly(ethylene glycol) 20000 (PEG20000) and α-cyclodextrin (α-CD)]. The catalytic performance of the Pickering emulsion that resulted from the formation of α-CD/PEG20000 crystallites at the oil droplet surface proved to be greatly dependent upon the presence of additives. We showed that controlled uploads of randomly methylated β-cyclodextrin (RAME-β-CD) within the supramolecular hydrogel could positively affect both the catalytic activity and chemoselectivity of the hydroformylation reaction. Conversely, no Pickering emulsion could be observed using excess RAME-β-CD, resulting in the subsequent degradation of the catalytic performance. Optical microscopy and optical fluorescence microscopy supported the catalytic results and allowed us to explain the role of RAME-β-CD. Indeed, controlled uploads of RAME-β-CD prevented the saturation of the oil droplet surface. RAME-β-CD acted as a fluidifier of the Pickering emulsion and accelerated the dynamics of exchange between the substrate-containing organic phase and the catalyst-containing hydrogel phase. Morever, RAME-β-CD acted as a receptor that participated in the conversion of the alkene by supramolecular means.
Pickering emulsions based on supramolecular hydrogels: Application to higher olefins' hydroformylation
Potier, Jonathan,Menuel, Stephane,Chambrier, Marie-Heleine,Burylo, Laurence,Blach, Jean-Francois,Woisel, Patrice,Monflier, Eric,Hapiot, Frederic
, p. 1618 - 1621 (2013/07/26)
Supramolecular hydrogels elaborated from a mixture of native α-cyclodextrin and poly(ethylene glycol)s in water proved to be effective media for higher olefins Rh-catalyzed hydroformylation due to the formation of Pickering emulsions.
An efficient conversion of carboxylic acids to one-carbon degraded aldehydes via 2-hydroperoxy acids
Akakabe, Yoshihiko,Nyuugaku, Takeshi
, p. 1370 - 1371 (2008/02/07)
After the formation of dianions of a carboxylic acid with lithium diisopropylamide, oxygen was bubbled into the solution to produce 2-hydroperoxy acid. Then the reaction mixture was acidified with a 2N HCl solution and subsequently elevated to 50°C to afford the aldehyde with the loss of one carbon atom. Even saturated (C10-C20) and unsaturated (C18:1) carboxylic acids were converted into the odd aldehydes (C9-C19, C17:1) in high yields. This conversion was found to be an efficient method for the preparation of carboxylic acids (Cn) to one-carbon degraded aldehydes (Cn-1) via 2-hydroperoxy acids.
