- A janus-headed lewis superacid: Simple access to, and first application of Me3Si-F-Al(ORF)3
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Upon reaction of gaseous Me3SiF with the in situ prepared Lewis acid Al(ORF)3, the stable ion-like silylium compound Me3Si-F-Al(ORF)3 1 forms. The Janusheaded 1 is a readily available smart Lewis acid that differentiates between hard and soft nucleophiles, but also polymerizes isobutene effectively. Thus, in reactions of 1 with soft nucleophiles (Nu), such as phosphanes, the silylium side interacts in an orbital-controlled manner, with formation of [Me3Si-Nu]+ and the weakly coordinating [F-Al(ORF)3]-or [(FRO)3Al-F-Al(ORF)3]- anions. If exchanged for hard nucleophiles, such as primary alcohols, the aluminum side reacts in a charge-controlled manner, with release of FSiMe3 gas and formation of the adduct R(H)O-Al(ORF)3. Compound 1 very effectively initiates polymerization of 8 to 21 mL of liquid C4H8 in 50 mL of CH2Cl2 already at temperatures between -57 and -30 8C with initiator loads as low as 10 mg in a few seconds with 100 % yield but broad polydispersities.
- Rohde, Michael,Muller, Lutz O.,Himmel, Daniel,Scherer, Harald,Krossing, Ingo
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supporting information
p. 1218 - 1222
(2014/04/03)
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- Trip2C6H3SeF: The first isolated selenenyl fluoride
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Joining the stable: The first examples of the highly instable selenenyl fluorides RSeF are prepared from the reaction on the tin selenide RSeSnMe 3 with XeF2. Through the use of extremely large protecting groups (m-terphenyl ligands) which stabilizes the RSeF units against disproportionation, the compounds could be isolated and characterized by NMR spectroscopy and single-crystal structure analysis (see structure). Copyright
- Poleschner, Helmut,Ellrodt, Stefan,Malischewski, Moritz,Nakatsuji, Jun-Ya,Rohner, Christian,Seppelt, Konrad
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experimental part
p. 419 - 422
(2012/03/22)
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- A novel, chemoselective and efficient microwave-assisted deprotection of silyl ethers with Selectfluor
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A novel microwave-assisted, chemoselective and efficient method for the cleavage of silyl ethers (aliphatic and aromatic) catalyzed by Selectfluor is reported. A wide range of TBS-, TIPS-, and TBDPS-protected alkyl silyl ethers can be chemoselectively cleaved in high yield in the presence of aryl silyl ethers. The chemoselective deprotection of phenolic TBS ethers, and not the TIPS- or TBDPS-protected phenolic ethers, and the deprotection of silyl esters were also achieved under these reaction conditions. In addition, the transetherification and etherification of benzylic hydroxy groups in alcoholic solvents is observed.
- Shah, Syed Tasadaque A.,Singh, Surendra,Guiry, Patrick J.
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experimental part
p. 2179 - 2182
(2009/07/01)
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- Synthesis of 3-fluorofuran-2(5H)-ones based on Z/E photoisomerisation and cyclisation of 2-fluoro-4-hydroxybut-2-enoates
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Mixtures of some (E)- and (Z)-2-fluoroalk-2-enoates prepared from the corresponding 2-hydroxycarbonyl compounds and ethyl 2-(diethoxyphosphoryl)-2- fluoroacetate have been transformed in high conversions into the target 3-fluorofuran-2(5H)-ones by an effi
- Pomeisl, Karel,Cejka, Jan,Kvicala, Jaroslav,Paleta, Oldrich
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p. 5917 - 5925
(2008/04/13)
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- Fluoroselenylation of acetylenes with xenon difluoride-diorganyl diselenides and xenon difluoride-phenylseleno(trialkyl)silanes
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A new, efficient method of fluoroselenenylation of terminal, and open-chain symmetric and unsymmetric disubstituted acetylenes and cycloalkynes, gives vicinal (E)-fluoroalkenyl selenides in moderate to high yields by addition of selenenyl fluoride equivalents. These are formed in situ from xenon difluoride and diaryl, dibenzyl or primary and secondary dialkyl diselenides. Alternatively, the benzeneselenenyl fluoride equivalent is formed by treatment of more reactive phenylselenotrialkylsilanes with xenon difluoride. The regiochemistry of the addition is strongly dependent on the steric effects of substituents bonded to the acetylene.
- Poleschner,Heydenreich,Spindler,Haufe
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p. 1043 - 1049
(2007/10/02)
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- METHYLAMMONIUM FLUORIDE (MAF): A CONVENIENT REAGENT FOR Si-O BOND CLEAVAGE
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Crude methylammonium fluoride prepared in a usual way is a very convenient reagent for Si-O bond cleavage.MAF is easy to prepare, easy to store and provides the desired deprotected alcohols without workup.
- Solladie-Cavallo, A.,Khiar, N.
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p. 1335 - 1340
(2007/10/02)
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