2004-70-8Relevant academic research and scientific papers
Asymmetric Counteranion Directed Catalytic Heck/Tsuji-Trost Annulation of Aryl Iodides and 1,3-Dienes
Xu, Jia-Cheng,Yin, Yi-Zhuo,Han, Zhi-Yong
supporting information, p. 3834 - 3838 (2021/05/26)
A chiral anion-mediated asymmetric Heck/Tsuji-Trost reaction of aryl iodides and 1,3-dienes is presented. Chiral indoline derivatives could be afforded with remarkably higher yields and enantioselectivities than our previous chiral ligand-based method. Silver carbonate is employed as both base and halide scavenger to ensure fast and recyclable exchange of the catalytic amount of chiral anions. Fast salt metathesis, as well as the acceleration effect of the chiral anion, could both benefit the stereocontrol of the reaction.
CATALYTIC HYDROCARBON DEHYDROGENATION
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Paragraph 0056; 0122; 0123, (2021/03/13)
A catalyst for dehydrogenation of hydrocarbons includes a support including zirconium oxide and Linde type L zeolite (L-zeolite). A concentration of the zirconium oxide in the catalyst is in a range of from 0.1 weight percent (wt. %) to 20 wt. %. The catalyst includes from 5 wt. % to 15 wt. % of an alkali metal or alkaline earth metal. The catalyst includes from 0.1 wt. % to 10 wt. % of tin. The catalyst includes from 0.1 wt. % to 8 wt. % of a platinum group metal. The alkali metal or alkaline earth metal, tin, and platinum group metal are disposed on the support.
Palladium-Catalyzed Chemoselective Protodecarboxylation of Polyenoic Acids
Al-Huniti, Mohammed H.,Perez, Mark A.,Garr, Matthew K.,Croatt, Mitchell P.
supporting information, p. 7375 - 7379 (2019/01/03)
Conditions for the first palladium-catalyzed chemoselective protodecarboxylation of polyenoic acids to give the desired polyenes in good yields are presented. The reactions proceed under mild conditions using either a Pd(0) or Pd(II) catalyst and tolerate a variety of aryl and aliphatic substitutions. Unique aspects of the reaction include the requirement of phosphines, water, and a polyene adjacent to the carboxylic acid.
Ring Opening of Biomass-Derived Cyclic Ethers to Dienes over Silica/Alumina
Kumbhalkar, Mrunmayi D.,Buchanan, J. Scott,Huber, George W.,Dumesic, James A.
, p. 5248 - 5256 (2017/08/17)
We show that cyclic ethers, such 2-methyltetrahydrofuran (2-MTHF), can undergo dehydration to produce pentadienes over SiO2/Al2O3. The catalyst exhibited reversible deactivation due to coke deposition, with the yield to pentadienes decreasing from 68% to 52% at 623 K over 58 h time on stream. A reaction network for 2-MTHF dehydration was proposed on the basis of the results of space time studies. Pentadienes can be produced directly by a concerted hydride shift and dehydration of carbenium intermediates or indirectly through dehydration of pentanal and pentenol. Reaction kinetics studies were performed at temperatures ranging from 573 to 653 K and 2-MTHF partial pressures from 0.21 to 2.51 kPa. The apparent activation energy barrier for 2-MTHF conversion to pentadienes and the reaction rate order for ring opening were determined to be 74 kJ mol-1 and 0.24, respectively, indicating strong interaction between 2-MTHF and the SiO2/Al2O3 surface. Other solid acids such as γ-Al2O3, H-ZSM-5, and Al-Sn-Beta were found to be active for 2-MTHF dehydration to pentadienes. The rate of ring opening decreased in the order 2,5-dimethyltetrahydrofuran > 2-MTHF > tetrahydropyran > tetrahydrofuran. Over SiO2/Al2O3, the dehydration of 2,5-dimethyltetrahydrofuran resulted in 75% yield to hexadiene isomers. (Figure Presented).
Production of renewable 1,3-pentadiene from xylitol via formic acid-mediated deoxydehydration and palladium-catalyzed deoxygenation reactions
Sun, Ruiyan,Zheng, Mingyuan,Li, Xinsheng,Pang, Jifeng,Wang, Aiqin,Wang, Xiaodong,Zhang, Tao
supporting information, p. 638 - 642 (2017/02/26)
A two-step synthetic approach for the production of renewable 1,3-pentadiene was reported: xylitol deoxydehydration (DODH) by formic acid to 2,4-pentadien-1-ol, 1-formate (2E), followed by deoxygenation to 1,3-pentadiene over Pd/C. The overall carbon yield of 1,3-pentadiene reached 51.8% under the optimized conditions.
High yields of piperylene in the transfer dehydrogenation of pentane catalyzed by pincer-ligated iridium complexes
Kumar, Akshai,Hackenberg, Jason D.,Zhuo, Gao,Steffens, Andrew M.,Mironov, Oleg,Saxton, Robert J.,Goldman, Alan S.
, p. 368 - 375 (2016/12/16)
Conjugated dienes are desirable reagents for several important applications. We report that sterically uncrowded PCP-pincer iridium complexes, including precursors of (iPr4PCP)Ir and (Me2tBu2PCP)Ir, catalyze the transfer d
New cofactor supports α,β-unsaturated acid decarboxylation via 1,3-dipolar cycloaddition
Payne, Karl A. P.,White, Mark D.,Fisher, Karl,Khara, Basile,Bailey, Samuel S.,Parker, David,Rattray, Nicholas J.W.,Trivedi, Drupad K.,Goodacre, Royston,Beveridge, Rebecca,Barran, Perdita,Rigby, Stephen E. J.,Scrutton, Nigel S.,Hay, Sam,Leys, David
supporting information, p. 497 - 501 (2015/07/02)
The bacterial ubiD and ubiX or the homologous fungal fdc1 and pad1 genes have been implicated in the non-oxidative reversible decarboxylation of aromatic substrates, and play a pivotal role in bacterial ubiquinone (also known as coenzyme Q) biosynthesis or microbial biodegradation of aromatic compounds, respectively. Despite biochemical studies on individual gene products, the composition and cofactor requirement of the enzyme responsible for in vivo decarboxylase activity remained unclear. Here we show that Fdc1 is solely responsible for the reversible decarboxylase activity, and that it requires a new type of cofactor: a prenylated flavin synthesized by the associated UbiX/Pad1. Atomic resolution crystal structures reveal that two distinct isomers of the oxidized cofactor can be observed, an isoalloxazine N5-iminium adduct and a N5 secondary ketimine species with markedly altered ring structure, both having azomethine ylide character. Substrate binding positions the dipolarophile enoic acid group directly above the azomethine ylide group. The structure of a covalent inhibitor-cofactor adduct suggests that 1,3-dipolar cycloaddition chemistry supports reversible decarboxylation in these enzymes. Although 1,3-dipolar cycloaddition is commonly used in organic chemistry, we propose that this presents the first example, to our knowledge, of an enzymatic 1,3-dipolar cycloaddition reaction. Our model for Fdc1/UbiD catalysis offers new routes in alkene hydrocarbon production or aryl (de)carboxylation.
CATALYTIC DEHYDRATION OF ALCOHOLS AND ETHERS OVER A TERNARY MIXED OXIDE
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Paragraph 0029; 0046, (2013/03/28)
A ternary V—Ti—P mixed oxide is shown to catalytically dehydrate 2-methyl-tetrahydrofuran in high conversion to give piperylene, in good yield. Volatile products collected from this reaction contain piperylene in concentrations as high as 80 percent by weight. Dehydration of glycerol to acrolein in high conversion and moderate selectivity is also demonstrated. The catalyst is also shown to dehydrate other alcohols and ether substrates. The catalyst is resistant to deactivation and maintains activity between runs.
Z-selective metathesis homocoupling of 1,3-dienes by molybdenum and tungsten monoaryloxide pyrrolide (MAP) complexes
Townsend, Erik M.,Schrock, Richard R.,Hoveyda, Amir H.
supporting information; experimental part, p. 11334 - 11337 (2012/09/05)
Molybdenum or tungsten monoaryloxide pyrrolide (MAP) complexes that contain OHIPT as the aryloxide (hexaisopropylterphenoxide) are effective catalysts for homocoupling of simple (E)-1,3-dienes to give (E,Z,E)-trienes in high yield and with high Z selectivities. A vinylalkylidene MAP species was shown to have the expected syn structure in an X-ray study. MAP catalysts that contain OHMT (hexamethylterphenoxide) are relatively inefficient.
Ni(0)-catalyzed 1,4-selective diboration of conjugated dienes
Ely, Robert J.,Morken, James P.
supporting information; experimental part, p. 4348 - 4351 (2010/11/19)
Figure Presented. A catalytic stereoselective 1,4-diboration of conjugated dienes with B2(pin)2 was accomplished with Ni(cod) 2 and PCy3 as the catalyst. This reaction broadens the substrate scope of current methods for catalytic diene diboration by including internal and sterically hindered dienes, and it proceeds efficiently at low catalyst loadings. The intermediate allylboronate was oxidized to the stereodefined allylic 1,4-diol.
