7560-64-7Relevant academic research and scientific papers
Iodine-Catalyzed Diels-Alder Reactions
Arndt, Thiemo,Wagner, Philip K.,Koenig, Jonas J.,Breugst, Martin
, p. 2922 - 2930 (2021/05/17)
The Diels-Alder cycloaddition is the most popular pericyclic reaction with numerous applications in synthesis and catalysis. We now demonstrate that we can perform this reaction under mild and metal-free conditions relying on molecular iodine as the catalyst. Cycloadditions with cyclohexadiene, cyclopentadiene, or isoprene with various dienophiles can be performed typically within minutes in moderate to good yields and high endo selectivity. The mechanistic studies including kinetic and DFT investigations clearly indicate a halogen-bond activation and rule out other modes of activation. Furthermore, iodine performs equally well as typical metallic Lewis acids like AlCl3, SnCl4, or TiCl4.
Selective production of bio-based: Para -xylene over an FeOx -modified Pd/Al2O3catalyst
Fu, Zaihui,Li, Changzhi,Meng, Qingwei,Pan, Xiaoli,Xiao, Yuxue,Zhang, Chao
supporting information, p. 4341 - 4349 (2020/07/14)
para-Xylene (PX) is a basic building block of polyethylene terephthalate, which is currently produced from petroleum resources. Developing a renewable route to PX is highly desirable to address both economic and environmental concerns. Several attempts used noble metal catalysts, e.g. Pd/Al2O3, to synthesize PX from biomass-derived 4-methyl-3-cyclohexene-1-carboxaldehyde (4-MCHCA), but suffered from a severe decarbonylation reaction, resulting in toluene as the main product. In this paper, we report an FeOx modification strategy to suppress the decarbonylation reaction on a Pd/Al2O3 catalyst, leading to a drastic shift in selectivity towards PX with a yield up to 81percent via a cascade dehydroaromatization-hydrodeoxygenation (DHA-HDO) pathway. Characterization and control experiments revealed that the electron density of Pd sites decreased in an FeOx-modified Pd/Al2O3 catalyst compared to Pd/Al2O3, thus tuning the preferential adsorption mode of the substrate from η2-(C,O), the key transition state of the decarbonylation reaction, to the η1-(O) mode that favors the hydrodeoxygenation process. Notably, this designed catalyst is highly stable and is readily applicable in the selective synthesis of a broad range of desired aromatic chemicals via the same DHA-HDO pathway from cyclohex-3-enecarbaldehyde derivatives. Overall, this work develops a controllable catalyst modification strategy that tailors an efficient catalyst for petroleum-independent bio-PX synthesis.
Selective Production of Renewable para-Xylene by Tungsten Carbide Catalyzed Atom-Economic Cascade Reactions
Dai, Tao,Li, Changzhi,Li, Lin,Zhao, Zongbao Kent,Zhang, Bo,Cong, Yu,Wang, Aiqin
supporting information, p. 1808 - 1812 (2018/02/10)
Tungsten carbide was employed as the catalyst in an atom-economic and renewable synthesis of para-xylene with excellent selectivity and yield from 4-methyl-3-cyclohexene-1-carbonylaldehyde (4-MCHCA). This intermediate is the product of the Diels–Alder reaction between the two readily available bio-based building blocks acrolein and isoprene. Our results suggest that 4-MCHCA undergoes a novel dehydroaromatization–hydrodeoxygenation cascade process by intramolecular hydrogen transfer that does not involve an external hydrogen source, and that the hydrodeoxygenation occurs through the direct dissociation of the C=O bond on the W2C surface. Notably, this process is readily applicable to the synthesis of various (multi)methylated arenes from bio-based building blocks, thus potentially providing a petroleum-independent solution to valuable aromatic compounds.
Selective Production of Toluene from Biomass-Derived Isoprene and Acrolein
Dai, Tao,Li, Changzhi,Zhang, Bo,Guo, Haiwei,Pan, Xiaoli,Li, Lin,Wang, Aiqin,Zhang, Tao
, p. 3434 - 3440 (2016/12/27)
Toluene is a basic chemical that is currently produced from petroleum resources. In this paper, we report a new route for the effective synthesis of toluene from isoprene and acrolein, two reactants readily available from biomass, through a simple two-step reaction. The process includes Diels–Alder cycloaddition of isoprene and acrolein in a Zn-containing ionic liquid at room temperature to produce methylcyclohex-3-enecarbaldehydes (MCHCAs) as intermediates, followed by M (M=Pt, Pd, Rh)/Al2O3-catalyzed consecutive dehydrogenation–decarbonylation of the MCHCAs at 573 K to generate toluene with an overall yield up to 90.7 %. Model reactions indicated that a synergistic inductive effect of the C=C double bond and the aldehyde group in MCHCA plays a key role in initiating the consecutive dehydrogenation–decarbonylation, and that methyl benzaldehydes are the key intermediates in the gas-phase transformation of MCHCAs. Microcalorimetric adsorption of CO on different catalysts showed that decarbonylation of the substrate occurs more likely on the strong adsorption sites. To the best of our knowledge, it is the first report of Pt/Al2O3-catalyzed consecutive dehydrogenation–decarbonylation of a given compound in one reactor. This work provides a highly efficient and environmental friendly route to toluene by utilizing two compounds that can be prepared from biomass.
Diels-alder reaction in air-and moisture-stable zinc-containing ionic liquids
Sun, I.-Wen,Wu, Shin-Yi,Su, Chia-Hao,Shu, Yu-Lin,Wu, Pei-Lin
, p. 367 - 370 (2015/02/05)
Diels-Alder reactions in a number of air- and moisture-stable dialkylimidazolium halide-ZnCl2 ionic liquids are reported. High yields and high endo selectivities have been observed. The ionic liquids could then be recyclable without loss of reactivity.
METHOD FOR PRODUCING p-XYLENE AND/OR p-TOLUALDEHYDE
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Paragraph 0048, (2014/12/12)
Disclosed is a method for producing p-xylene and/or p-tolualdehyde with high yield through a short process using biomass resource-derived substances as raw materials. The method for producing p-xylene and/or p-tolualdehyde of the present invention comprises: a cyclization step of producing 4-methyl-3-cyclohexenecarboxaldehyde from isoprene and acrolein; and an aromatization step of producing p-xylene and/or p-tolualdehyde from 4-methyl-3-cyclohexenecarboxaldehyde by gas-phase flow reaction using a catalyst(s).
A sustainable procedure for highly enantioselective organocatalyzed Diels-Alder cycloadditions in homogeneous ionic liquid/water phase
De Nino, Antonio,Bortolini, Olga,Maiuolo, Loredana,Garofalo, Angelo,Russo, Beatrice,Sindona, Giovanni
experimental part, p. 1415 - 1417 (2011/06/10)
The MacMillan iminium catalyst was investigated for asymmetric Diels-Alder cycloadditions in ionic liquid/H2O homogeneous phase. Superior selectivity, product yield, and shorter reaction times were observed in comparison with classical organic solvents. Additional advantages are the easy synthetic procedure, the excellent recovery of products, and the recyclability of the whole system.
Microwave-assisted aza-Prins reaction. Part 1: Facile preparation of natural-like 3-azabicyclo[3.3.1]non-6-enes
Parchinsky, Vladislav,Shumsky, Alexei,Krasavin, Mikhail
scheme or table, p. 7157 - 7160 (2012/01/04)
A facile and operationally simple route to diastereomerically pure, natural-like 3-azabicyclo[3.3.1]non-6-enes via microwave-assisted, BF 3·OEt2-promoted aza-Prins reaction has been developed. Complexity-generating transformations based on these products involving reactive functionalities introduced during the aza-Prins step have been developed.
Immobilization of macMillan imidazolidinone as mac-SILC and its catalytic performance on sustainable enantioselective dielsAlder cycloaddition
Hagiwara, Hisahiro,Kuroda, Toshihiro,Hoshi, Takashi,Suzuki, Toshio
experimental part, p. 909 - 916 (2010/07/05)
MacMillan's imidazolidinone catalyst was immobilized as a supported ionic liquid catalyst (Mac-SILC) in the pores of silica gel with the aid of an ionic liquid - 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide. The heterogenized organocatalyst was utilized for the enantioselective Diels-Alder reaction of cyclopentadiene and cinnamaldehyde, recovered by simple filtration and subsequent evacuation, and repeatedly used up to six times in 81% average chemical yield, 87% ee for endo- and 80% ee for exo-products. The Mac-SILC was effective for a variety of substrates.
Erbium triflate in ionic liquids: A recyclable system of improving selectivity in Diels-Alder reactions
Bortolini, Olga,De Nino, Antonio,Garofalo, Angelo,Maiuolo, Loredana,Procopio, Antonio,Russo, Beatrice
experimental part, p. 124 - 129 (2011/02/16)
The efficiency of Er(OTf)3 in promoting the Diels-Alder reactions between different dienes and dienophiles in ionic liquids has been investigated. Compared with the analogous cycloadditions performed in conventional solvents shorter reaction times are required to obtain good/excellent yields. In most cases an enhancement of regio- and endo:exo selectivity was observed. The role of the ionic liquid, as a function of the cationic part, i.e. the imidazolium based or the pyridinium based, is discussed well. The ILs containing the catalyst can be readily separated from the reaction products and recovered in very high purity for direct reuse, up to six cycles.
