18022-66-7Relevant articles and documents
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Bruns,K. et al.
, p. 2523 - 2530 (1979)
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Poly(ethylene glycol)-Supported Chiral Imidazolidin-4-one: An Efficient Organic Catalyst for the Enantioselective Diels-Alder Cycloaddition
Benaglia, Maurizio,Celentano, Giuseppe,Cinquini, Mauro,Puglisi, Alessandra,Cozzi, Franco
, p. 149 - 152 (2002)
A tyrosine-derived imidazolidin-4-one was immobilized on a modified poly(ethylene glycol) and converted in situ into a soluble polymer-supported catalyst for the enantioselective Diels-Alder cycloaddition of acrolein to 1,3-cyclohexadiene (up to 92% ee) a
Polyesters Containing Chiral Imidazolidinone Salts in Polymer Main Chain: Heterogeneous Organocatalysts for the Asymmetric Diels–Alder Reaction
Haraguchi, Naoki,Nguyen, Thanh Liem,Itsuno, Shinichi
, p. 3786 - 3794 (2017)
Novel main-chain polyesters functionalized with chiral imidazolidinone salts were successfully synthesized. Polycondensation of a chiral imidazolidinone dimer bearing two hydroxyphenyl groups with selected achiral dicarboxylic acid chlorides followed by t
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.