1074-61-9Relevant articles and documents
Bifunctional polymeric organocatalysts and their application in the cooperative catalysis of Morita-Baylis-Hillman reactions
Kwong, Cathy Kar-Wing,Huang, Rui,Zhang, Minjuan,Shi, Min,Toy, Patrick H.
, p. 2369 - 2376 (2007)
A series of soluble, noncross-linked polystyrene-supported tri-phenylphosphane and 4-dimethylaminopyridine reagents were prepared. Some of these polymeric reagents contained either alkyl alcohol or phenol groups on the polymer backbone. The use of these materials as organocatalysts in a range of Morita-Baylis-Hillman reactions indicated that hydroxyl groups could participate in the reactions and accelerate product formation. In the cases examined, phenol groups were more effective than alkyl alcohol groups for catalyzing the reactions. This article is one of the first reports of the synthesis and use of non-natural, bifunctional polymeric reagents for use in organic synthesis in which both functional groups can cooperatively participate in the catalysis of reactions.
Synthesis and application of polytetrahydrofuran-grafted polystyrene (PS-PTHF) resin supports for organic synthesis
Shimomura, Osamu,Se Lee, Byoung,Meth, Sergio,Suzuki, Hiroki,Mahajan, Suresh,Nomura, Ryoki,Janda, Kim D.
, p. 12160 - 12167 (2005)
Cross-linked polystyrene (PS) with polytetrahydrofuran (PTHF) chains were prepared for use in solid phase organic synthesis (SPOS). The resins were prepared from styrene, styrene-PTHF macromonomers and cross-linkers 1,4-bis[4-vinylphenoxy]butane or divinylbenzene by suspension polymerization. The styrene-PTHF macromonomers were prepared by cationic polymerization of 4-vinylbenzyl bromide and 4-(4-vinylphenoxy)butyl iodide activated by silver hexafluoroantimonate and 4-(5-hydroxypentyl)styrene activated by triflic anhydride. Alternatively, polytetrahydrofuran-grafted polystyrene (PS-PTHF) resins could also be directly prepared from 5-hydroxypentyl JandaJel by cationic polymerization using triflic anhydride as the initiator. These PS-PTHF resins exhibited good swelling characteristics across a wide spectrum of polar and non-polar solvents. These resins were used in the synthesis of 3-methyl-1-phenyl-2-pyrazolin-5-one, which requires β-ketoester formation at low temperature (-78°C), resulting in good yield and product purity; whereas the same synthesis carried out on PEG-grafted PS (PS-PEG) resin resulted in incomplete synthesis.
High refractive index transparent nanocomposites prepared by in situ polymerization
Tsai, Chieh-Ming,Hsu, Sheng-Hao,Ho, Chun-Chih,Tu, Yu-Chieh,Tsai, Hsin-Chien,Wang, Chung-An,Su, Wei-Fang
, p. 2251 - 2258 (2014)
High refractive index transparent nanocomposites have been developed by in situ polymerization of a precursor that contains functional monomers and surface modified anatase TiO2 nanoparticles for optoelectronic applications. The monomers are in the liquid form, so environmentally friendly solventless precursors can be prepared. The precursor can be processed into various shapes or thick films (>50 microns) of the nanocomposite. The relationships of the chemical structure of the organic matrix, nanoparticle content and dispersity with the refractive index, transparency, mechanical and thermal properties are systematically investigated. The refractive index, and mechanical and thermal properties of the nanocomposite are increased with increasing TiO2 content and aromatic structure in the organic matrix due to their rigid characteristics. The transparency of the nanocomposite is increased with increasing TiO2 content and dispersity. At the same loading of nanoparticles, the higher dispersity and the better transparency are due to the less extent of Rayleigh scattering. At 18 vol% (60 wt%) of TiO2, the acetic acid modified TiO2/poly(4-vinyl benzyl alcohol) nanocomposite has a refractive index of 1.73 and excellent transparency (>85% from 500 nm to 800 nm). The refractive index of the nanocomposite can be further increased to 1.77 by replacing aliphatic acetic acid modified TiO2 with aromatic phenyl acetic acid modified TiO2. The results of this work provide new knowledge and a new pathway to design a polymer based high refractive index material.
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Emerson et al.
, p. 1905 (1947)
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Optimization of polystyrene-supported triphenylphosphine catalysts for aza-Morita-Baylis-Hillman reactions
Zhao, Lin-Jing,Kwong, Cathy Kar-Wing,Shi, Min,Toy, Patrick H.
, p. 12026 - 12032 (2005)
A series of polar group functionalized polystyrene-supported phosphine reagents were examined as catalysts in the aza-Morita-Baylis-Hillman reactions of N-tosyl arylimines and a variety of Michael acceptors with the aim of identifying the optimal polymer/solvent combination. For these reactions JandaJel-PPh3 (1 mmol PPh3/g loading) resin containing methoxy groups (JJ-OMe-PPh3) on the polystyrene backbone in THF solvent provided the highest yield of all the catalyst/solvent combinations examined. The methyl ether groups were incorporated into JJ-OMe-PPh3 using commercially available 4-methoxystyrene, and thus such polar polystyrene resins are easily accessible and should find utility as nucleophilic catalyst supports.
In-situ facile synthesis novel N-doped thin graphene layer encapsulated Pd@N/C catalyst for semi-hydrogenation of alkynes
Lin, Shanshan,Liu, Jianguo,Ma, Longlong,Sun, Jiangming
, (2021/12/03)
Transition metal-catalyzed semi-hydrogenation of alkynes has become one of the most popular methods for alkene synthesis. Specifically, the noble metal Pd, Rh, and Ru-based heterogeneous catalysts have been widely studied and utilized in both academia and industry. But the supported noble metal catalysts are generally suffering from leaching or aggregation during harsh reaction conditions, which resulting low catalytic reactivity and stability. Herein, we reported the facile synthesis of nitrogen doped graphene encapsulated Pd catalyst and its application in the chemo-selective semi-hydrogenation of alkynes. The graphene layer served as “bulletproof” over the active Pd Nano metal species, which was confirmed by X-ray and TEM analysis, enhanced the catalytic stability during the reaction conditions. The optimized prepared Pd@N/C catalyst showed excellent efficiency in semi-hydrogenation of phenylacetylene and other types of alkynes with un-functionalized or functionalized substituents, including the hydrogenation sensitive functional groups (NO2, ester, and halogen).
A method of synthesis of alcohols
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Paragraph 0079-0084, (2022/01/10)
The present invention belongs to the field of organic synthesis technology, specifically a synthesis method of an alcohol; the present invention is under the catalytic action of tert-butanol lithium, with ester compounds and pinacol borane as raw materials, tetrahydrofuran as a solvent, reacted at 100 ° C for 24h, followed by adding 2mol / LNaOH / MeOH solution, stirred at room temperature overnight to obtain alcohol compounds; the raw materials of the present invention are of extensive sources or easy to prepare, the reaction conditions are relatively mild and do not require a large number of / cumbersome additives, in addition to the tert-butanol lithium catalyst is simple, And the prepared alcohol compounds are of high quality and high separation yield.
Nickel(II) Catalyzed Hydroboration: A Route to Selective Reduction of Aldehydes and N-Allylimines
Hossain, Istiak,Schmidt, Joseph A. R.
, p. 1877 - 1884 (2020/05/25)
A cationic [(iminophosphine)nickel(allyl)]+ complex was found to be sufficiently electrophilic to activate aldehydes and N-allylimines to undergo hydroboration with pinacolborane (HBpin) under mild reaction conditions. The catalyst displayed excellent selectivity toward aldehydes in the presence of ketones. A wide variety of functional groups were tolerated, including halogens, NO2, CN, OMe, and alkenes for both aldehydes and imines. Electron-rich substrates were found to be significantly more reactive than their electron poor counterparts, a feature that was correlated to their enhanced ability to coordinate to the Lewis acidic nickel center.
