- Synthesis of PS/PO-chimeric oligonucleotides using mixed oxathiaphospholane and phosphoramidite chemistry
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Chimeric oligonucleotides containing phosphodiester and phosphorothioate linkages have been obtained using the solid phase synthesis. The oligonucleotide parts possessing natural internucleotide phosphate bonds were assembled using commercially available
- Radzikowska, Ewa,Baraniak, Janina
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- Proton-Coupled Electron Transfer Enables Tandem Radical Relay for Asymmetric Copper-Catalyzed Phosphinoylcyanation of Styrenes
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A tandem radical relay strategy was realized for the first Cu(I)-catalyzed enantioselective phosphinocyanation of styrenes. In this reaction, tBuOOSiMe3 generated in situ from tBuOOH serves as a radical initiator to trigger t-butoxy radical production upon oxidization of L?Cu(I) species via proton-coupled-electron transfer (PCET) pathway, which leads to sequential phosphinoyl radical and benzyl radical formations. The resultant β-cyanodiarylphosphine oxides could be easily converted to a series of chiral ?-amino phosphine ligands.
- Zhang, Guoyu,Fu, Liang,Chen, Pinhong,Zou, Jianping,Liu, Guosheng
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supporting information
p. 5015 - 5020
(2019/09/03)
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- Determination of silyl peroxides by ultra-performance liquid chromatography/electrospray ionisation mass spectrometry
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Rationale: Residual initiators in polymers are a concern in the case of products that come directly into contact with the human body or food. Due to low concentrations and difficulties in the sample preparation, highly sensitive and selective methods are required. Methods: A series of bis-silyl- and alkyl-silyl peroxides were analysed by electrospray ionisation mass spectrometry (ESI-MS) on an ultra-performance liquid chromatography/time-of-flight (UPLC/TOF) instrument. Li, Na, K, and NH4 acetates were used to promote the formation of [M + Me]+ ions. The sample preparation involved only dissolution of the polymer sample in 0.1 mL of acetonitrile, followed by precipitation with 1 mL of water. A portion of 0.1–1 μL of the solution was then analysed without further treatment by UPLC/ESI-MS. Results: Limits of detection (LODs) were in the range of 0.06–9 pmol, depending on the peroxide structure. On average, the signal intensity increased with the number of phenyl groups in a peroxide and decreased in the order Na > Li > K > NH4. Peroxides that did not contain phenyl groups could not be detected. Collision-induced dissociation experiments can be used for structural investigations of alkyl-silyl peroxides. It was possible to detect 2 × 10?4% (LOD = 7 × 10?5%) of unreacted Ph3SiOOt-Bu in the poly(methyl methacrylate) sample. Conclusions: The method is suitable for the analysis of trace peroxide initiators in polymers and for other purposes where LODs in the pmol range are required.
- Krawczyk, Tomasz,Zalewski, Mariusz,Szo?tysik, Rafa?,Korytkowska-Wa?ach, Anna
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p. 2040 - 2046
(2018/11/10)
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- Reactions of hydroxyl-containing compounds with tert-butyl hydroperoxide in the presence of chromium tetra-tert-butoxide
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Primary and secondary aliphatic, alkylaromatic, cyclic, and organoelement alcohols are efficiently oxidized by tert-butyl hydroperoxide in the presence of both equimolar and catalytic quantities of chromium tetra-tert-butoxide (C6H6, 20°C). α-Diols containing tertiary hydroxyl groups interact with this system via oxidative splitting of the carbon scaffold. The oxidation includes the stages of formation and decomposition of chromium-containing peroxy compounds. Further transformations of the carbonyl compounds depend on the structure of radicals in the molecules.
- Stepovik,Zaburdaeva,Fukin,Karaghiosoff
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p. 2547 - 2559
(2015/12/30)
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- Conversion of primary sulfones into α-silyloxysulfones and aldehydes
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Lithiated primary sulfones were converted into α-trimethylsilyloxysulfones using t-butyl trimethylsilyl peroxide (BTSP).Hydrolysis then led to the corresponding aldehydes.Keywords - sulfonylcarbanion / t-butyl-trimethylsilyl peroxide / α-silyloxysulfones / aldehydes
- Chemla, F.,Julia, M.,Uguen, D.
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p. 547 - 553
(2007/10/02)
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