7605-51-8Relevant academic research and scientific papers
Mechanism of di-tert-butylsilylene transfer from a silacyclopropane to an alkene
Driver, Tom G.,Woerpel
, p. 10659 - 10663 (2007/10/03)
Kinetic and thermodynamic studies of the reactions of cyclohexene silacyclopropane 1 and monosubstituted alkenes suggested a possible mechanism for di-tert-butylsilylene transfer. The kinetic order in cyclohexene silacyclopropane 1 and cyclohexene were de
Chemical and spectroscopic studies related to the Lewis acidity of lithium perchlorate in diethyl ether
Springer, Gerald,Elam, Chanda,Edwards, Anna,Bowe, Craig,Boyles, David,Bartmess, John,Chandler, Martin,West, Kevin,Williams, Jan,Green, James,Pagni, Richard M.,Kabalka, George W.
, p. 2202 - 2210 (2007/10/03)
Polarimetric studies on camphor (2) as well as IR studies on crotonaldehyde (CA;1) and benzonitrile (BN;3) confirm the conclusion of a previously published NMR study on crotonaldehyde that lithium perchlorate (LP) weakly binds to probe bases in diethyl ether (DE). The weak binding is a consequence of the fact that the lithium ion (actually the LP ion pair and higher aggregates), a powerful Lewis acid in the gas phase, competitively binds to ether and the added base. Methylene camphor (5), (E)-1,3-pentadiene (4), camphene, and phenylacetylene (6) do not bind to LP in DE. Shifts to lower energy of the C=O modes of CA in ether solutions containing increasing amounts of LP are consistent with moderate increases in solvent polarity. Only small or no shifts are seen in the C≡N modes of BN and its 1:1 complex with added LP. Because the C≡N and especially C=O modes are blue shifted under external applied pressure, the large internal pressures of LP/DE do not mimic external applied pressure. Likewise, the small or no changes observed in λ(max) for the absorption and emission spectra of anthracene (9) and azulene (8) in ether as a function of LP concentration do not conform to what is observed under external applied pressure. Studies of the Diels-Alder reaction of (E)-1,3-pentadiene with methyl acrylate show that the reaction is entirely catalyzed in LP/DE; polarity and internal pressure do not influence product selectivity in this reaction.
Studies of the Transition-state Structure by the Method of Volumetric Steric Effects. Part 4. Transition State in Diels-Alder Reactions of (E)-1-Alkyl(alkoxy)buta-1,3-dienes with Alkyl Acrylates
El'yanov, Boris S.,Shakhova, Svetlana K.,Polkovnikov, Boris D.,Rar, Lev F.
, p. 11 - 16 (2007/10/02)
A method of studying transition-state structures by analysis of volumetric steric effects is proposed.The method is used to reveal features of the steric structure of the transition state in Diels-Alder reactions.The structure has been found to change from one approximating the structure of the prereactional complex to that resembling the half-chair adduct as the diene substituent changes from methyl to t-butyl.As this takes place, no intermediate half-boat adduct is formed.An increase in steric hindrance during the change in the substituent is regarded as the driving force responsible for the transition-state shift along the reaction co-ordinate.This is consistent with the Hammond postulate.The C=O and C=C groups of the dienophile in the endo-transition state are in the s-cis-conformation.
STUDIES OF COMPOUNDS IN THE MENTHANE SERIES. XIX. SYNTHESIS AND PROPERTIES OF TRANS-o-4-MENTHEN-8-OL AND STEREOISOMERIC o-5-METHEN-8-OLS
Bazyl'chik, V. V.,Fedorov, P. I.,Klyuev, N. A.,Dank, E. Kh.
, p. 1320 - 1327 (2007/10/02)
Trans-o-4-Menthen-8-ol and cis- and trans-o-5-menthen-8-ols have been prepared via the Diels-Alder reactions of 1,3-butadiene with crotonaldehyde in the presence of boron trifluoride etherate, and piperylene with methyl acrylate, respectively.The dehydration reactions of these alcohols have been studied in the presence of acetic anhydride and potassium bisulfate; the latter reagent demonstrates a high reaction selectivity.
