1592-12-7Relevant articles and documents
Visible light-promoted dihydroxylation of styrenes with water and dioxygen
Yang, Bo,Lu, Zhan
supporting information, p. 12634 - 12637 (2017/12/02)
An efficient visible light promoted metal-free dihydroxylation of styrenes with water and dioxygen has been developed for the construction of vicinal alcohols. The protocol was operationally simple with a broad substrate scope. The mechanistic studies demonstrated that one of the hydroxyl groups came from water and the other one came from molecular oxygen. Additionally, the β-alkyoxy alcohols could also be obtained using a similar strategy.
Structurally Defined Molecular Hypervalent Iodine Catalysts for Intermolecular Enantioselective Reactions
Haubenreisser, Stefan,W?ste, Thorsten H.,Martnez, Claudio,Ishihara, Kazuaki,Muiz, Kilian
supporting information, p. 413 - 417 (2016/01/25)
Molecular structures of the most prominent chiral non-racemic hypervalent iodine(III) reagents to date have been elucidated for the first time. The formation of a chirally induced supramolecular scaffold based on a selective hydrogen-bonding arrangement provides an explanation for the consistently high asymmetric induction with these reagents. As an exploratory example, their scope as chiral catalysts was extended to the enantioselective dioxygenation of alkenes. A series of terminal styrenes are converted into the corresponding vicinal diacetoxylation products under mild conditions and provide the proof of principle for a truly intermolecular asymmetric alkene oxidation under iodine(I/III) catalysis.
Synthesis and characterization of cross-linkable ruthenium dye with ion coordinating property for dye-sensitized solar cells
Liu, Ken-Yen,Ko, Chih-Yang,Ho, Kuo-Chuan,Lin, King-Fu
scheme or table, p. 3318 - 3324 (2012/05/31)
Crosslinkable ruthenium complex dye, Ru(2,2′-bipyridine-4,4′- bicarboxylic acid)(4,4′-bis((4-vinyl benzyloxy)methyl)-2,2′- bipyridine)(NCS)2 (denoted as Ru-S dye), was synthesized and characterized using 1H-NMR, 13C-NMR, Fourier transform infrared (FTIR) and UV/vis spectroscopies.The power conversion efficiency of dye-sentitized solar cell (DSSC) using Ru-S and liquid electrolyte containing lithium iodide (LiI) reached 7.53% under standard global AM 1.5 full sunlight, which is partly attributed to Li+ being coordinated by Ru-S as verified by ATR-FTIR spectroscopy. As Ru-S was further crosslinked with glycerol propoxylate triacrylate (GPTA), not only 89% of dye retained on TiO2 mesoporous surface after rinsed by 0.1 N NaOH aqueous solution, the power efficiency was also increased to 7.88%. As poly(methyl acrylate) was used to gel the electrolyte system, the power efficiency of DSSC with Ru-S dye was 6.96% but increased to 7.57% after crosslinking with GPTA. Notably, both DSSCs showed a good long-term stability after one month storage.
The formation of core cross-linked star polymers containing cores cross-linked by dynamic covalent imine bonds
Jackson, Alexander W.,Fulton, David A.
supporting information; experimental part, p. 6051 - 6053 (2010/11/02)
Diblock copolymers possessing amino or aldehyde functions within one of their blocks were prepared using RAFT polymerization techniques. These polymers were shown to cross-link through dynamic imine bonds to form core cross-linked star polymers which display a size-dependency upon the concentration at which the cross-linking reactions are performed.
Ruthenium-catalyzed, one-pot alcohol oxidation-wittig reaction producing αβ unsaturated esters
Lee, Eun Young,Kim, Youngkwon,Lee, Jae Sung,Park, Jaiwook
supporting information; experimental part, p. 2943 - 2946 (2009/10/11)
By a one-pot process, αβ-unsaturated esters were synthesized in high yield through the Ru-catalyzed oxidation of primary alcohols and the coupling of the resulting aldehydes and stabilized Wittig reagents. The ruthenium catalyst is composed of ruthenium nanoparticles embedded in aluminum oxyhydroxide and can be recovered simply by filtration or decantation. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009.
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 (2008/02/02)
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.
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 (2007/10/03)
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.
Synthesis and color tuning properties of blue highly fluorescent vinyl polymers containing a pendant pyrrolopyridazine
Mitsumori, Teruyuki,Craig, Ian M.,Martini, Ignacio B.,Schwartz, Benjamin J.,Wudl, Fred
, p. 4698 - 4704 (2007/10/03)
We report here the synthesis, polymerization, and properties of highly fluorescent vinyl polymers containing pendant pyrrolopyridazines. Their luminescence quantum efficiencies can be as high as 60%, and all polymers showed strong luminescence even in the solid state, which is indicative of little self-quenching in these systems. The polymers were processable into films, fibers, and rods that were suitable for several device applications. The fibers and rods showed interesting end luminescence whose colors were tunable by manipulating their geometries.
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 (2007/10/03)
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.
