- Photocatalytic Properties of a Palladium Metallosquare with Encapsulated Fullerenes via Singlet Oxygen Generation
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Singlet oxygen has recently attracted a great deal of attention due to its strong oxidizing properties, which makes it useful in organic synthesis and biological studies. However, the photosensitizers that are required for singlet oxygen generation remain
- Martínez-Agramunt, Víctor,Peris, Eduardo
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supporting information
p. 11836 - 11842
(2019/09/03)
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- A domino Kornblum-DeLaMare/aza-Michael reaction of 3,6-dihydro-1,2-dioxines and application to the synthesis of the ceramide transport inhibitor (±)-HPA-12
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A Kornblum-DeLaMare/aza-Michael reaction of 3,6-dihydro-1,2-dioxines with primary and secondary amines has been developed which affords 4-hydroxy-3-aminoketones. The aza-Michael products were reduced using non-selective NaBH4/MeOH or diastereoselective (up to 92:8) SnCl4/NaBH4 conditions yielding (1R?,3S?)-3-amino-1,4-diols in up to 97% and 70% yield respectively. The major reduction product was converted in two steps to (±)-HPA-12, which is an inhibitor of the cytosolic ceramide transporting protein.
- Legendre, Sarah V.A.-M.,Jevric, Martyn,Klepp, Julian,Sumby, Christopher J.,Greatrex, Ben W.
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p. 1229 - 1239
(2017/12/04)
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- Continuous Endoperoxidation of Conjugated Dienes and Subsequent Rearrangements Leading to C-H Oxidized Synthons
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We have investigated the continuous flow photooxidation of several conjugated dienes and subsequent rearrangement using a practical and safe continuous-flow homemade engineered setup. End-to-end approaches involving endoperoxidation, Kornblum-DeLaMare rearrangement, and additional rearrangements are comprehensively detailed with optimization, scope, and scale-up to obtain useful hydroxyenones, furans, and 1,4-dicarbonyl building blocks.
- De Souza, Juliana M.,Brocksom, Timothy J.,McQuade, D.Tyler,De Oliveira, Kleber T.
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p. 7574 - 7585
(2018/06/11)
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- Photosensitized oxidation of alkenes with dendrimers as microreactors: Controllable selectivity between energy and electron transfer pathway
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Carboxylic acid terminated poly(aryl ether) dendrimers were used as microreactors to conduct the photooxidation of trans-stilbene and trans,trans-1,4-diphenyl-1,3-butadiene (DPB) sensitized by 9,10- dicyanoanthracene (DCA) in aqueous media. The photooxidation pathways can be successfully controlled by encapsulating the substrate and sensitizer molecules in the same or different sets of dendrimers. The singlet oxygen can transfer from one dendrimer to another. After the photoreaction, products could be more easily extracted from a dendrimer than from a micelle or a vesicle, and the dendrimer can be simply recovered by neutralization of the solution and reused. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
- Yuan, Zhao,Zheng, Shaojun,Zeng, Yi,Chen, Jinping,Han, Yongbin,Li, Yingying,Le, Yi
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experimental part
p. 718 - 722
(2010/06/19)
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- Vesicle controlled selectivity in photosensitized oxidation of olefins
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The photooxidation of α-pinene (α-PE) and trans,trans-1,4-diphenyl- 1,3-butadiene (DPB) sensitized by 9,10-dicyanoanthracene (DCA) in mixed surfactant vesicles was selectively directed toward either the singlet oxygen mediated or the superoxide radical an
- Li, Hong Ru,Wu, Li Zhu,Tung, Chen Ho
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p. 1085 - 1086
(2007/10/03)
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- Photosensitized oxidation of alkenes adsorbed on pentasil zeolites
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Photosensitized oxidation of trans, trans-1,4-diphenyl-1,3-butadiene (DPB), trans-stilbene (TS), and 2,3-dihydro-γ-pyran (DHP) included in the internal framework of Na-ZSM-5 zeolites was investigated. The zeolite samples having adsorbed the alkenes were suspended in isooctane or pentaerythritol trimethyl ether (PTE), and the sensitizers, 9,10-dicyanoanthracene (DCA) and hypocrellin A (HA), were dissolved in the solution. The molecular sizes of both of the sensitizers and the solvents are greater compared with the channels of the zeolites. The isolation of the alkenes within the zeolites from the sensitizers in surrounding solution prevents them from undergoing electron transfer. On the other hand, singlet oxygen was produced in the solution and diffused into the internal framework of the zeolites to react with the alkenes. Thus, only singlet oxygen oxidation products were obtained and no product derived from superoxide radical anion was detected. By addition of water after the alkene adsorption, the photosensitized oxidation product distributions can be dramatically varied depending upon the aluminum content of the zeolite framework and the molecular dimensions of the substrates. Possible interpretations of these effects are discussed in terms of the locations of the reactants.
- Tung, Chen-Ho,Wang, Hongwei,Ying, Yun-Ming
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p. 5179 - 5186
(2007/10/03)
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- Remarkable product selectivity in photosensitized oxidation of alkenes within nafion membranes
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9,10-Dicyanoanthracene (DCA)-sensitized photooxidation of trans,trans- 1,4-diphenyl-1,3-butadiene (DPB), trans-stilbene (TS), and α-pinene (PE) incorporated in Nafion membranes has been investigated. While the oxidation in homogeneous solution yields the products derived from both the energy transfer and the electron transfer pathways, that within Nafion membranes selectively gives either the singlet oxygen mediated or the superoxide radical anion mediated products depending on the status and location of the substrate and sensitizer molecules in the reaction media. Upon incorporating the alkene within the water-swollen Nafion membranes and dissolving DCA in the surrounding CH2Cl2 solution, the sensitizer is isolated from the substrate during the irradiation time and the electron transfer between them is prevented. The singlet oxygen produced in the surrounding solution diffuses into the Nafion clusters and reacts with the alkenes. Thus, only the singlet oxygen oxidation products are obtained and no product derived from superoxide radical anion is detected. In contrast, incorporating both the substrate and the sensitizer within the water-swollen Nafion membranes leads to the possibility of situating the two dissimilar molecules near one another within the restricted space of the Nafion cluster. Thus, the electron transfer from the alkenes to the singlet excited state of DCA is enhanced, and the efficiency of the intersystem crossing from 1DCA* to 3DCA* is reduced. The photosensitized oxidation in this case only gives products derived from the electron-transfer pathway, and no singlet oxygen mediated product is observed.
- Tung, Chen-Ho,Guan, Jing-Qu
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p. 11874 - 11879
(2007/10/03)
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- SENSITIZED PHOTO-OXYGENATION OF ACYCLIC CONJUGATED DIENES
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Sensitized photo-oxygenation of a wide variety of acyclic 1,3-dienes was investigated.The 1,4-cycloaddition of singlet oxygen to acyclic conjugated dienes was closely related to the thermal Diels-Alder reaction in stereospecificity, and steric and electronic effects of substituents.Reactivity order of singlet oxygen toward conjugated dienes and isolated C-C double bonds was exhibited as follows: trisubstituted monoolefins > 2-substituted 1,3-dienes > disubstituted mono-olefins.
- Matsumoto, Masakatsu,Dobashi, Satoshi,Kuroda, Keiko,Kondo, Kiyosi
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p. 2147 - 2154
(2007/10/02)
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