- A one-step co-condensation method for the synthesis of well-defined functionalized mesoporous SBA-15 using trimethallylsilanes as organosilane sources
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A new method for the preparation of well-defined functionalized mesoporous SBA-15 has been developed by a one-step co-condensation method using trimethallylsilanes as organosilane sources. This new method enables the incorporation of various bulky organic functional groups with long alkyl chain tethers into the mesoporous silica network.
- Han, Ye Ri,Park, Jung-Woo,Kim, Hanil,Ji, Hyejeong,Lim, Soo Hyun,Jun, Chul-Ho
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supporting information
p. 17084 - 17087
(2015/12/01)
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- Conjugate Addition Reactions of Allylic Copper Species Derived from Grignard Reagents: Synthetic and Spectroscopic Aspects
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A general study on the 1,4-addition chemistry of allyl, methallyl, crotyl, and prenyl Grignard-derived organocopper reagents has been conducted.While diallylic cuprates formed from such species are not effective Michael donors, the 1:1:1 combination of an
- Lipshutz, Bruce H.,Hackmann, Claus
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p. 7437 - 7444
(2007/10/02)
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- Synthesis of the Bicyclo Ring Systems from 4-Allylcyclobutenones. Intramolecular Ketene/Alkene Cycloadditions
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A general synthesis of bicycloheptenones from 4-allylcyclobutenones is described.The rearrangement is envisaged to involve an electrocyclic ring opening of the cyclobutenone and subsequent intramolecular 2 + 2 cycloaddition of the resulting vinylketene to the nonconjugated allylic alkene moiety.This method is particularly suitable for the synthesis of highly substituted derivatives since the regiochemistry of the substitution pattern is convenienty controlled.The scope of the rearrangement and the mechanism are discussed.
- Xu, Simon L.,Xia, Haiji,Moore, Harold W.
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p. 6094 - 6103
(2007/10/02)
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- Mechanical Activation of Magnesium Turnings for the Preparation of Reactive Grignard Reagents
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Preactivation of magnesium by dry stirring in an inert atmosphere is highly beneficial for the clean synthesis of reactive allylic or benzylic organomagnesium chlorides.This procedure routinely produces 0.4 M solutions of the Grignard reagent in diethyl ether free from coupling products.The purity may be directly assayed by 13C spectroscopy.Using spin saturation transfer techniques, the rate constant for interconversion of the enantiomers of (1-phenyl-2-methylpropyl)magnesium chloride in Et2O at 25 deg C was shown to be -1.Electron microscopy has been used to define the surface changes occurring during the dry stirring of magnesium turnings.
- Baker, Karen V.,Brown, John M.,Hughes, Nigel,Skarnulis, A. Jerome,Sexton, Ann
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p. 698 - 703
(2007/10/02)
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- Use of Magnesium Anthracene * 3 THF in Synthesis: Generation of Grignard Compounds and Other Reactions with Organic Halides
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The course (a), (b), (c) (Scheme 1) of the reaction of magnesium anthracene * 3 THF (1) with organic halides (RX) is dependent on the nature of RX.With alkyl halides in THF 1 reacts as a nucleophile, whereby primary as well as secondary alkyl halides produce dialkyldihydroanthracenes (4-4'') and tertiary alkyl halides yield primarily monoalkyl-substituted dihydroanthracenes (2, 2').With bromo- and iodobenzene in THF 1 reacts predominantly as a radical with H atom abstraction from the solvent affording benzene and 9.The formation of Grignard compounds (5) and anthracene (6), originating from primary and secondary alkyl and aryl halides and 1 in toluene or ether at elevated temperatures, is not caused by the reaction of 1 but by the "active magnesium" (Mg*) formed by decomposition of 1 in these solvents.In contrast, allyl, propargyl, and benzyl halides react with 1 independently of the solvent under mild conditions to produce 5 and 6.Allyl- and the difficultly accessible allenylmagnesium chloride can be prepared in THF at -78 and 0 deg C, respectively, from the corresponding halides and ordinary Mg powder via catalytic amounts of 1.
- Bogdanovic, Borislav,Janke, Nikolaus,Kinzelmann, Hans-Georg
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p. 1507 - 1515
(2007/10/02)
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- Active Magnesium from Catalytically Prepared Magnesium Hydride or from Magnesium Anthracene and its Uses in the Synthesis
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Highly reactive, pyrophoric forms of magnesium with specific surface areas of 20-109 m2/g (Mg*) can be generated by the dehydrogenation of catalytically prepared magnesium hydride (MgH2*) or by decomposition of magnesium anthracene * 3 THF (4).The decomposition of 4, with recovery of anthracene and THF, may be accomplished both thermally and by ultrasound in an organic solvent (toluene, n-heptane) or thermally in the solid state in vacuo.Mg* obtained by the latter method exhibits only weak reflections in the X-ray powder diagram and has, in comparison to other mentioned Mg* species, the highest reactivity toward hydrogen.Diverse Grignard compounds can be prepared under mild conditions (* from MgH2* or 4.The cleavage of THF with formation of 1-oxa-2-magnesiacyclohexane (2) is possible by employing Mg* from NgH2* or 4.
- Bartmann, Ekkehard,Bogdanovic, Borislav,Janke, Nikolaus,Liao, Shijan,Schlichte, Klaus,et al.
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p. 1517 - 1528
(2007/10/02)
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