25723-74-4Relevant academic research and scientific papers
Regioselective oxygenations of s-trans dienes, silyl dienol ethers (SDEs), by triphenyl phosphite ozonide (TPPO) and its mechanistic study
Mori,Abe,Nojima
, p. 3548 - 3553 (2007/10/03)
The direct oxygenation of s-trans dienes, silyl dienol ethers (SDEs) 2, by triphenyl phosphite ozonide (TPPO) has been examined in detail. The regioselective oxygenation was found to give hydroperoxide 3, alcohol 4, ketone 5, dimer 6, and peroxy phosphate 7 with concomitant formation of triphenyl phosphate 8 and diphenyl trimethylsilyl phosphate 10. The formation of peroxy phosphate 7 was found for the first time in TPPO oxygenation reactions. The low temperature31P and1H NMR spectroscopic analyses proved the direct reaction of SDEs with TPPO without generation of singlet oxygen. The formation of the oxygenated products 3-7 is reasonably explained by the intervention of the zwitterion ZI, which can be formed by the nucleophilic attack of SDE to the central oxygen of the ozonide. The regioselective attack of SDE to the central oxygen of the ozonide was supported by the quantum chemical calculation (B3LYP/6-31G*).
THE NATURE AND CONSEQUENCES OF THE INTERACTION OF PHOSPHORYL NUCLEOPHILES WITH A TRIORGANOSILYL CHLORIDE
Chojnowski, J.,Cypryk, M.,Michalski J.,Wozniak, L.
, p. 275 - 282 (2007/10/02)
In order to throw light on the possible role of positively charged tetra-coordinate silicon intermediates in the racemization of α-NpPhMeSiCl (1) induced by uncharged nucleophiles two sets of kinetic studies have been carried out.In the first the rates of two reactions namely racemization of 1 catalysed by (PhO)2(Me3SiO)P=O (2) and transsilylation of 2 with 1, which take place together and are believed to involve the same intermediate were determined; the transsilylation was found to be faster than the racemization, and involved transient formation of an optically active product.In the second the racemization of 1 catalysed by HMPT in various CCl4/CH2Cl2 mixtures was studied; the rate was found to increase markedly with increase in the dielectric constant of the medium.The results of both sets of experiments were consistent with a mechanism involving a silyloxyphosphonium cation intermediate.
Erzeugung und Nachweis des Silaethens Me2Si=C(SiMe3)2: Thermischer Zerfall von (Me3Si)2(Me2XSi)CLi (X z. B. Hal, OR, SR)
Wiberg, Nils,Preiner, Gerhard,Schieda, Oswald,Fischer, Gerd
, p. 3505 - 3517 (2007/10/02)
Thermal decomposition of Me2XSi-CLi(SiMe3)2 (1,LiX) in diethyl ether at -102 to 10 deg C leads under intramolecular LiX-elimination (X = Hal, TosO, Ph2POn, PhS) to 1,3-disilacyclobutane 2 (2).The reactive intermediate product is the silae
The Dealkylation of Phosphate and Phosphonate Esters by Iodotrimethylsilane: A Mild and Selective Procedure
Blackburn, G. Michael,Ingleson, David
, p. 1150 - 1153 (2007/10/02)
Iodotrimethylsilane transforms alkyl esters of phosphorus oxyacids into their corresponding trimethylsilyl esters and alkyl iodide.The reaction is rapid and quantitative at room temperature.The reagent has no effect on aryl phosphate ester functions or upon alkyl carboxylate, ether, bromoalkane, vinyl, and ethynyl functions under the conditions employed for transesterification.The trimethylsilyl esters can be isolated by distillation or solvolysed without purification using methanol or water to afford dealkylated phosphate and phosphonate species.Selective monodealkylation of dialkyl phosphonates cannot be achieved using only one equivalent of the reagent, wich leads to the formation of mixed products.
