10141-72-7Relevant academic research and scientific papers
The Stereochemistry of the Cyclic β-Halogeno-ether Synthesis of Olefinic Alcohols
Crombie, Leslie,Wyvill, Robert D.
, p. 1056 - 1058 (1984)
The (Z)/(E) composition of olefinic alcohols produced by sodium ring-scission of cyclic β-halogeno-ethers can be accounted for by a mechanism involving fast electron transfer and carbanion inversion, with ring-cleavage speedier than conformational inversion.
STEREOSELECTIVE SYNTHESIS OF CYCLIC ETHERS VIA BROMINE ASSISTED EPOXIDE RING EXPANSION
Davies, Stephen G.,Polywka, Mario E. C.,Thomas, Susan E.
, p. 1461 - 1464 (1985)
9-Oxabicyclonon-4-ene reacts with bromine to give stereoselectively trans,trans-2,6-dibromo-9-oxabicyclononane and trans,trans-2,5-dibromo-9-oxabicyclononane.
Mesoporous ZSM-5 zeolite-supported ru nanoparticles as highly efficient catalysts for upgrading phenolic biomolecules
Wang, Liang,Zhang, Jian,Yi, Xianfeng,Zheng, Anmin,Deng, Feng,Chen, Chunyu,Ji, Yanyan,Liu, Fujian,Meng, Xiangju,Xiao, Feng-Shou
, p. 2727 - 2734 (2015)
Zeolite-based catalysts have been widely used in the conversion of biomass recently, but the catalytic yields of the desired products are strongly limited by the relatively small micropores of zeolite. Here, we reported a hierarchically porous ZSM-5 zeolite with micropore and b-axis-aligned mesopore-supported Ru nanoparticles (Ru/HZSM-5-OM) that are highly efficient for the hydrodeoxygenation of both small and bulky phenolic biomolecules to the corresponding alkanes. Compared with the conventional ZSM-5 zeolite-supported Ru catalyst, the high catalytic activities and alkane selectivities over Ru/HZSM-5-OM are attributed to the abundant exposed acidic sites in HZSM-5-OM with open mesopores. This feature is potentially important for future phenolic bio-oil upgrading.
Solvomercuration-Demercuration. 8. Oxymercuration-Demercuration of Methoxy-, Hydroxy-, and Acetoxy-Substituted Alkenes
Brown, Herbert C.,Lynch, Gary J.
, p. 531 - 538 (1981)
The oxymercuration-demercuration (OM-DM) of a series of methoxy-, hydroxy-, and acetoxy-substituted alkenes was examined.The systems examined were the allyl, crotyl, 3-buten-1-yl, 4-penten-1-yl, and 5-hexen-1-yl.The methoxyalkenes undergo hydration with very high regioselectivity and almost quantitative yield in all cases.However, a small -I effect is observed in the case of the allylalkene (97.1percent Markovnikov vs. 99.5percent in 1-hexene).Moreover, in the crotyl case, a major directing effect is observed: 97.7percent 3-ol, 2.3percent 2-ol.The other three alkenes undergo the OM reaction with no effect from the methoxy group (99.5percent Markovnikov isomer).In contrast, only allyl-, crotyl-, and 3-buten-1-yl alcohols produce major amounts of hydrated products, the diols.While no hydroxyl group directing effect is observed in the allyl system, a major one is again seen in the case of the crotyl: 93.5percent l,3-diol and 6.5percent l,2-diol.The major products from the 4-penten-1-yl and 5-hexen-1-yl and alcohols are 2-methyltetrahydrofuran and 2-methyltetrahydropyran, respectively, resulting from OH-5 and OH-6 neighboring group participation in the OM stage.The acetoxy alkenes undergo hydration to give diols in ca. 80percent yield with ca. 20percent unreacted starting material.This is the result of a competitive deoxymercuration reaction which is occurring in the DM stage.However, the yield of hydrated products can be increased by varying the amount of base used in the DM.Neighboring-group participation, AcO-5, is observed in the allyl system only, resulting in a 65percent yield of the Markovnikov oxymercurial, by 1H NMR analysis, and a 35percent yield of the acetoxy-exchanged mercurial.Again, a major -I-directing effect of the acetoxy group was observed in the crotyl system but not in the others.In addition to the expected l,2- and l,3-diols, the OM-DM of crotyl acetate also resulted in small amounts of the unexpected 2,3-diol under kinetic conditions.Finally, a modified DM procedure has been developed which is compatible with the acetoxy group.
CHIMIE ORGANOMETALLIQUE SOUS HAUTE PRESSION: REACTION DES CHLOROCETONES AVEC L'HYDRURE DE TRIBUTYLETAIN
Degueil-Castaing, M.,Maillard, B.,Rahm, A.
, p. 49 - 56 (1985)
High-pressure reaction of tributyltin hydride with several chloroketones (3-chloro-2-butanone, 4-chloro-2-butanone, 5-chloro-2-pentanone, 6-chloro-2-hexanone and 7-chloro-2-heptanone) led to the formation of chloroalkoxytins or cyclic ethers.An ionic mechanism, starting with nucleophilic attack at the carbonyl group, is proposed to explain the formation of the reaction products.
Cobalt-Catalyzed Intermolecular Hydrofunctionalization of Alkenes: Evidence for a Bimetallic Pathway
Zhou, Xiao-Le,Yang, Fan,Sun, Han-Li,Yin, Yun-Nian,Ye, Wei-Ting,Zhu, Rong
supporting information, p. 7250 - 7255 (2019/05/16)
A functional group tolerant cobalt-catalyzed method for the intermolecular hydrofunctionalization of alkenes with oxygen- and nitrogen-based nucleophiles is reported. This protocol features a strategic use of hypervalent iodine(III) reagents that enables a mechanistic shift from conventional cobalt-hydride catalysis. Key evidence was found supporting a unique bimetallic-mediated rate-limiting step involving two distinct cobalt(III) species, from which a new carbon-heteroatom bond is formed.
Strongly Lewis Acidic Metal-Organic Frameworks for Continuous Flow Catalysis
Ji, Pengfei,Feng, Xuanyu,Oliveres, Pau,Li, Zhe,Murakami, Akiko,Wang, Cheng,Lin, Wenbin
supporting information, p. 14878 - 14888 (2019/10/02)
The synthesis of highly acidic metal-organic frameworks (MOFs) has attracted significant research interest in recent years. We report here the design of a strongly Lewis acidic MOF, ZrOTf-BTC, through two-step transformation of MOF-808 (Zr-BTC) secondary building units (SBUs). Zr-BTC was first treated with 1 M hydrochloric acid solution to afford ZrOH-BTC by replacing each bridging formate group with a pair of hydroxide and water groups. The resultant ZrOH-BTC was further treated with trimethylsilyl triflate (Me3SiOTf) to afford ZrOTf-BTC by taking advantage of the oxophilicity of the Me3Si group. Electron paramagnetic resonance spectra of Zr-bound superoxide and fluorescence spectra of Zr-bound N-methylacridone provided a quantitative measurement of Lewis acidity of ZrOTf-BTC with an energy splitting (?E) of 0.99 eV between the ?x? and ?y? orbitals, which is competitive to the homogeneous benchmark Sc(OTf)3. ZrOTf-BTC was shown to be a highly active solid Lewis acid catalyst for a broad range of important organic transformations under mild conditions, including Diels-Alder reaction, epoxide ring-opening reaction, Friedel-Crafts acylation, and alkene hydroalkoxylation reaction. The MOF catalyst outperformed Sc(OTf)3 in terms of both catalytic activity and catalyst lifetime. Moreover, we developed a ZrOTf-BTC?SiO2 composite as an efficient solid Lewis acid catalyst for continuous flow catalysis. The Zr centers in ZrOTf-BTC?SiO2 feature identical coordination environment to ZrOTf-BTC based on spectroscopic evidence. ZrOTf-BTC?SiO2 displayed exceptionally high turnover numbers (TONs) of 1700 for Diels-Alder reaction, 2700 for epoxide ring-opening reaction, and 326 for Friedel-Crafts acylation under flow conditions. We have thus created strongly Lewis acidic sites in MOFs via triflation and constructed the MOF?SiO2 composite for continuous flow catalysis of important organic transformations.
Investigation and mechanistic study into intramolecular hydroalkoxylation of unactivated alkenols catalyzed by cationic lanthanide complexes
Zhu, Xuehua,Li, Guoyao,Xu, Fan,Zhang, Yong,Xue, Mingqiang,Shen, Qi
, p. 1451 - 1458 (2017/02/19)
Cationic lanthanide complexes of the type [Ln(CH3CN)9]3+[(AlCl4)3]3–·CH3CN (Ln = Pr, Nd, Sm, Gd, Er, Yb, Y) served as effective catalysts for the intramolecular hydroalkoxylation/cyclization of unactivated alkenols to yield the cyclic ethers with Markovnikov regioselectivity under mild conditions. Novel cationic complexes, [AlCl(CH3CN)5]2+[(AlCl4)2]2–·CH3CN and [Nd(CH3CN)9]3+[(FeCl4)3]3–·CH3CN, were synthesized and evaluated for the intramolecular hydroalkoxylation/cyclization of unactivated alkenols for comparison. The active sequence of [Nd(CH3CN)9]3+[(FeCl4)3]3–·CH3CN 3CN)5]2+[(AlCl4)2]2–·CH3CN 3CN)9]3+[(AlCl4)3]3–·CH3CN observed indicated that both the cation and anion have great influence on the activity. Comparative study on the activity of AlCl3and its cationic complex [AlCl(CH3CN)5]2+[(AlCl4)2]2–·CH3CN revealed the formation of the cationic Al center enhanced the activity greatly. The1H NMR studies indicated the activation of hydroxyl and olefin by the cationic Ln3+center were involved in the reaction pathways.
Catalytic conversion of sorbitol to gasoline-ranged products without external hydrogen over Pt-modified Ir-ReOx/SiO2
Liu, Sibao,Okuyama, Yasuyo,Tamura, Masazumi,Nakagawa, Yoshinao,Imai, Akio,Tomishige, Keiichi
, p. 122 - 131 (2016/05/11)
Deoxygenation of sorbitol was carried out over a Pt-modified Ir-ReOx/SiO2 catalyst in biphasic solvent system (n-decane + H2O) without external hydrogen. Good yield of gasoline-ranged products was obtained including C5-C6 alkanes and C2-C6 mono-functionalized compounds such as ketones, alcohols, cyclic ethers and carboxylic acids. The Pt(3 wt%)-Ir-ReOx/SiO2 catalyst showed the best performance in the production of gasoline-ranged products. The maximum yield of gasoline-ranged products was 42%. The distribution of the products can be tuned by the addition of HZSM-5. The main products were C5-C6 alkanes with addition of HZSM-5 while the main products were C2-C6 mono-functionalized compounds without addition of HZSM-5. Characterizations such as TPR, XRD, TEM, XANES, EXAFS, CO adsorption were performed. The results demonstrated that the Pt-Ir-ReOx/SiO2 catalyst showed the structure of Pt-Ir alloy particles partially covered with ReOx species. The number of surface Pt atoms in Pt(3)-Ir-ReOx/SiO2 was larger than that of Pt/SiO2 or Pt-ReOx/SiO2 because of the small size of Pt-Ir alloy particles. The large number of surface Pt atoms and the synergetic effect of Pt, Ir and ReOx species make the catalyst efficiently generate hydrogen by aqueous phase reforming of sorbitol, and the generated hydrogen is consumed in the hydrogenolysis C-O bonds.
Aqueous-phase hydrogenation and hydrodeoxygenation of biomass-derived oxygenates with bimetallic catalysts
Lee, Jechan,Kim, Yong Tae,Huber, George W.
supporting information, p. 708 - 718 (2014/02/14)
The reaction rate on a per site basis for aqueous-phase hydrogenation (APH) of propanal, xylose, and furfural was measured over various alumina-supported bimetallic catalysts (Pd-Ni, Pd-Co, Pd-Fe, Ru-Ni, Ru-Co, Ru-Fe, Pt-Ni, Pt-Co, and Pt-Fe) using a high-throughput reactor (HTR). The results in this paper demonstrate that the activity of bimetallic catalysts for hydrogenation of a carbonyl group can be 110 times higher than monometallic catalysts. The addition of Fe to a Pd catalyst increased the activity for hydrogenation of propanal, xylose, and furfural. The Pd1Fe3 catalyst had the highest reaction rate for APH of propanal among all catalysts tested in the HTR. The addition of Fe to the Pd catalyst increased the reaction rate for xylose hydrogenation by a factor of 51, compared to the monometallic Pd catalyst. However, no bimetallic catalyst tested in this study was more active than the monometallic Ru catalyst for hydrogenation of xylose. The Pd1Fe 3 catalyst had the highest reaction rate for APH of furfural, which was 9 times higher than the rate of the Pd catalyst. The Pd1Fe 3/Zr-P, a bimetallic bifunctional catalyst, was 14 times more active on a per site basis than a Pd/Zr-P catalyst for aqueous-phase hydrodeoxygenation (HDO) of sorbitol in a continuous flow reactor. The addition of Fe to the Pd catalyst increased the rate of C-C cleavage reactions and promoted the conversion of sorbitan and isosorbide in HDO of sorbitol. Pd1Fe 3/Zr-P also had a higher yield of gasoline-range products than the Pd/Zr-P catalyst.
