41885-43-2Relevant articles and documents
The Yukawa-Tsuno relationship for the β-silicon effect in the solvolysis rates of 2-(aryldimethylsilyl)ethyl chlorides
Fujio, Mizue,Uchida, Mai,Okada, Ayumi,Alam, Md. Ashadul,Fujiyama, Ryoji,Siehl, Hans-Ullrich,Tsuno, Yuho
, p. 1834 - 1842 (2007/10/03)
Solvolysis rates of 2-(aryldimethylsilyl)ethyl chlorides were determined conductimetrically in 60% (v/v) aqueous ethanol. The effects of aryl substituents at the silyl atom on the solvolysis rates at 50°C were correlated with essentially nonresonant σ parameters of r = 0:10 in terms of Yukawa-Tsuno (Y-T) Eq. 1, giving a ρ value of -1:75. Such a high ρ value may be regarded as the effect of aryl ring on the bridged Si in the rate-determining step. The Si-bridging is consistent with the fact that the solvolysis of the unsubstituted substrate with d2-labeled ethylene moiety gave substitution products with label scrambling. The arylsilyl substituent effects were likewise analyzed for several relevant sets of β-silyl systems in order to ascertain significant variations of ρ values from system to system; Y-T Eq. 1 correlated quite excellently with essentially nonresonant sigmas of negligible resonance demand (r ? 0:10), to exhibit significant variations of ρ from -1:75 to -0:95.
The preparation of polymer beads by photocationic suspension co-polymerisation of 2-(arylsilyl)ethyl vinyl ethers
Porres, Laurent,Deleuze, Herve,Landais, Yannick
, p. 2198 - 2203 (2007/10/03)
Polymer beads have been prepared by photocationic suspension polymerisation of 2-(aryldimethyl)silyl ethers in perfluorooctane in the course of our studies on polymer-supported desymmetrisation of 1-silacyclohexa-2,5-dienes. Good yields of 100-200 μm beads of satisfactory shape have been obtained using a perfluorinated co-polymer as stabilising agent. These beads have no permanent porosity although they have a high nominal cross-linking level. Their swelling in common organic solvents is comparable with those of Merrifield or TentaGel gel-type resins.
β-Dimethylphenylsilylethyl esters: A linker for solid-phase chemistry
Alonso, Concepción,Nantz, Michael H.,Kurth, Mark J.
, p. 5617 - 5622 (2007/10/03)
Preparation of a β-dimethylphenylsilylethyl (BMPSE) ester linker from 2% divinylbenzene-styrene copolymer by lithiation, chlorodimethylvinylsilane silylation, hydroboration/oxidation (giving 9), and O-acylation is reported. The resulting polymer-bound BMPSE esters were employed in a reaction sequence consisting of RCHO→RCH=NOH→isoxazoline/isoxazole (giving 12). (C) 2000 Elsevier Science Ltd.
Synthesis and Application of Bis-Silylethyl-Derived Phosphate-Protected Fmoc-Phosphotyrosine Derivatives for Peptide Synthesis
Chao, Hann-Guang,Bernatowicz, Michael S.,Reiss, Paul D.,Matsueda, Gary R.
, p. 6687 - 6691 (2007/10/02)
Three Fmoc-phosphotyrosine derivatives with silylethyl-based phosphate protection were synthesized and evaluated for use in peptide synthesis.The stability of these derivatives toward piperidine/DMF (1:4) treatment and their cleavability with TFA solutions were examined.On the basis of these data, the bis-protected Fmoc-phosphotyrosine derivative or Fmoc-Tyr(PO3MDPSE2)-OH, was shown to be the most suitable candidate for the production of phosphotyrosine peptides.The syntheses of phosphotyrosine peptides including one containing Met and Cys are described.
Substituent Effect on Solvolysis of 2-(Aryldimethylsilyl)ethyl Chlorides
Fujiyama, Ryoji,Munechika, Toshihiro
, p. 5907 - 5910 (2007/10/02)
The solvolysis rates of 2-(aryldimethylsilyl)ethyl chlorides 3 were measured using a conductometric method.The analysis of the Yukawa-Tsuno LArSR equation gives a reaction constant of ρ=-1.42 and a high resonance demand of r=1.48.This result indicates that the β-silicon effect is attributed to the cyclic transition state structure with a positive charge on the silicon in this primary system.
