19244-53-2Relevant academic research and scientific papers
Reactions of trimethylsilyl-derived iodohydrins with electron-rich π-systems
Ishai, Eti,Shamai, Sarit,Feit, Ben-Ami
, p. 434 - 438 (2007/10/03)
Reactions of trimethylsilyl-derived iodohydrins of the type R1R2CH-CH(I)OTMS, with electron-rich olefins, and the effects of certain factors on these reactions, were studied. The trimethylsilyl-derived iodohydrins were obtained in situ by reacting R1R2CH-CHO (R1 = R2 = H; R1 = H, R2 = alkyl, phenyl) with TMSI. The corresponding trimethylsilyl enol ether derivatives (R1R2C=CH-OTMS), and 1,1-diarylethylenes were the olefins used. Aldehydes of the type RCH2-CH=O reacted smoothly in the presence of TMSI to yield the condensation product RCH2-CH=C(R)-CH=O. Both RCH(-CH=CAr2)2 and the cyclic acetal 5 were obtained as main products of the RCH=O-TMSI-CH2=CAr2 reaction system, depending on the [RCHO]:[TMSI]:[CH2=CAr2] concentration ratio. The mechanisms of formation for the various main products and by-products are discussed. TMSI substitutes, formed by reacting Me3SiCl with each of several Lewis acids, were also used.
1,1-Diphenylethylene adsorbed onto acid zeolites: Nature of the blue (605-nm) species
Fornes, Vicente,Garcia, Hermenegildo,Jovanovic, Slobodan,Marti, Vicente
, p. 4715 - 4726 (2007/10/03)
Diffuse reflectance spectra of HY (Si/Al 15) and Hβ (Si/Al 13) zeolites after adsorption of 1,1-diphenylethylene (DPE) show an intense 605-nm absorption band characteristic of an elusive blue species observed a long time ago for DPE-silica-alumina solids. This blue species was wrongly attributed to the corresponding DPE+. radical cation or a complex of DPE with Lewis sites of these solids. In our case, EPR spectra of DPE samples adsorbed on HY and Hβ zeolites indicate that the spin population of these samples is too low (15 spin · g-1) to contain significant amounts of any paramagnetic species. In addition, IR spectra of the organic material incorporated within HY and Hβ is very similar to those of some DPE dimers. Product studies after solid-liquid extraction of zeolites and silica-alumina in which DPE has been adsorbed also show the formation of the corresponding dimers derived from the acid-catalyzed mechanism. Variable amounts of oxidation products are also formed when the adsorption is carried out in the open air. In addition, 13C-NMR spectra in solution of blue samples generated by treatment of DPE with sulfuric acid in dimethyl sulfate also indicate the presence of the same dimer distribution and the absence of detectable low-field signals that could be attributed to any carbenium ion. With these data, it is clear that in spite of the intense color developed in these samples, the bulk of the organic material adsorbed on the zeolites does not correspond to any intermediate, but to dimers. Semiempirical ROHF calculations using the ZINDO program provide some support to the possibility that the blue color could be due to 1,1,3,3-tetraphenyl-1-butylium cation, the reaction intermediate involved in the DPE dimerization mechanism.
Carbanion Photochemistry. 2. Kinetic Control of Product Formation in Reactions of Radicals with Carbanions
Tolbert, Laren M.
, p. 3531 - 3534 (2007/10/02)
The interaction of resonance-stabilized carbanions with methyl radicals produced by the irradiation of the carbanions in dimethyl sulfoxide is governed by the pKa of the carboanion conjugate acid to a greater extent than by the stability of the
REACTION OF BENZENE WITH PHENYLACETYLENE IN THE PRESENCE OF H3PO4*BF3
Ryabov, V. D.,Korobkov, V. Yu.
, p. 337 - 340 (2007/10/02)
In contrast to the known reactions of phenylacetylene with aromatic compounds, which lead to the formation of a mixture of phenylarylethylenes and phenyldiarylethanes, the reaction of benzene with phenylacetylene gives high yields of either 1-methyl-1,3,3-triphenylindane (III) or 1-methyl-1,3-diphenylindene (IV), depending on the conditions.In addition to the above-mentioned compounds, 1,1-diphenylethylene (I) and its dimer, 1,1,3,3-tetraphenyl-1-butene (II) were found in the reaction products.
