13703-52-1Relevant articles and documents
Catalysis by temporary covalent activation. A novel catalysis of unactivated Diels-Alder reactions
Singleton, Daniel A.,Leung, Shun-Wang,Martinez, Jose P.,Lee, Yu-Kai
, p. 3163 - 3166 (1997)
Diels-Alder reactions of cis-2-chlorovinyltributylstannane are greatly accelerated by the presence of catalytic amounts of haloboranes. Mechanistic studies support a mechanism for the catalysis involving an intermediate boron-aclivated dienophile. A simil
Synthesis of cyclic sulfones by ring-closing metathesis.
Yao, Qingwei
, p. 427 - 430 (2007/10/03)
A general and highly efficient synthesis of cyclic sulfones based on ring-closing metathesis has been developed. The synthetic utility of the resulting cyclic sulfones was demonstrated by their participation in stereoselective Diels-Alder reactions and transformation to cyclic dienes by the Ramberg-Baecklund reaction.
Isotope effects and the distinction between synchronous, asynchronous, and stepwise Diels-Alder reactions
Singleton, Daniel A.,Schulmeier, Brian E.,Hang, Chao,Thomas, Allen A.,Leung, Shun-Wang,Merrigan, Steven R.
, p. 5149 - 5160 (2007/10/03)
A variety of symmetrical or nearly symmetrical Diels-Alder reactions are studied by a combination of experimental isotope effects, theoretical calculations, and rate observations. Becke3LYP calculations predicted highly asynchronous transition structures for Diels-Alder reactions of bis(boryl)acetylenes, dialkyl acetylenedicarboxylates, triazolinediones, and dialkyl maleates. Rate observations and kinetic isotope effects are consistent with these predictions, though the experimental support for the calculated structures is notably ambiguous in some cases. A concerted mechanism is supported for the retro-Diels-Alder reaction of norbornene. Overall, Diels-Alder reactions appear to be only very weakly biased toward synchronous transition states.
In situ formation of alkenyl- and alkynylboranes for Diels-Alder reactions by boron-silicon exchange with alkenyl- and alkynylsilanes
Singleton, Daniel A.,Leung, Shun-Wang
, p. 157 - 161 (2007/10/03)
A variety of alkenylsilanes underwent transmetallation with BBr3 to afford the corresponding alkenyldibromoboranes in solution. Similarly, the transmetallation of alkynylsilanes with BCl3 afforded alkynyldichloroboranes, A number of the alkenyl- and alkynylboranes are novel and useful Diels-Alder dienophiles. An ionic mechanism for the transmetallation is proposed.
Photokondensation in Benzoldampf durch einzelne UV-Laserblitze
Kauer, M.,Wagner, H. Gg.
, p. 109 - 128 (2007/10/02)
Benzene vapour was photolysed with single pulses of an Excimer laser at wavelength of 248 nm.The formation of aerosol could be followed using Laser light absorption and scattering, gaseous products were analysed by gas-chromatography (and GC-MS).At low laser energies mainly biphenyl and phenylcyclohexadiene are formed, from laser energies of about 30 mJ/(pulse cm2) upward multiphotonabsorption becomes important and C2H2 formation increases strongly.At the conditions applied aerosol is formed mainly via condensation of biphenyl and phenylcyclohexadiene.At approximately constant degree of photolysis an increase of temperature reduces the supersaturation of these two compounds, and the formation of aerosol decreases; it also decreases when the laser energies and benzene concentrations are reduced.An increase of total pressure and of benzene partial pressure up to a certain level increase the aerosol formation.The growth with time of particle number density and size is described. - Keywords: Benzene photolysis / Photocondensation / Aerosol / Excimer laser / Ignition
CYCLO-CODIMERIZATION OF 1,3-BUTADIENE DERIVATIVES WITH NON-ACTIVATED TERMINAL ACETYLENES CATALYZED BY CATIONIC RHODIUM(I) COMPLEX
Matsuda, Isamu,Shibata, Masahiro,Sato, Susumu,Izumi, Yusuke
, p. 3361 - 3362 (2007/10/02)
An efficient cyclo-codimerization between 1,3-diene and non-activated terminal acetylene has been attained by the catalysis of PF6 to give 1,4-disubstituted cyclohexa-1,3-dienes under mild conditions.
Irradiation of Tetraphenylborate Does Not Generate a Borene Anion
Wilkey, John D.,Schuster, Gary B.
, p. 2118 - 2122 (2007/10/02)
In contrast to a previous claim, irradiation of sodium tetraphenylborate in acetonitrile or THF solution does not result in the formation of the diphenylborene anion.Stilbenes, formed from irradiation in the presence of diphenylacetylene and thought to ha