6206-25-3Relevant articles and documents
Indium-mediated, highly efficient cyclopropanation of olefins using CH 2I2 as methylene transfer reagent
Virender,Jain, Suman L.,Sain, Bir
, p. 37 - 38 (2007/10/03)
The indium-mediated, one-pot cyclopropanation of a variety of olefins with methylene iodide proceeds smoothly with excellent yields of products.
A Study on the Reducing Abilities of Tris(alkylthio)silanes
Chatgilialoglu, C.,Guerra, M.,Guerrini, A.,Seconi, G.,Clark, K. B.,et al.
, p. 2427 - 2433 (2007/10/02)
Tris(methylthio)silane and tris(isopropylthio)silane effectively reduce a variety of organic substrates via free radical mechanisms.These silanes can also be used as hydrosilylating agents for alkenes having electron-donating substituents.The bond dissociation energy of the Si-H bonds have been measured by photoacoustic calorimetry and found to be around 83 kcal mol-1.The absolute rate constants for the reaction of the tert-butoxyl radical with (RS)3SiH have been measured by a laser flash photolysis technique and the optical absorption spectra of the correspondingradicals have been obtained.Multiple scattering Xα calculations showed that the dominant absorption detected in the UV-vis region was due to ?Si-S(e) -> SOMO and SOMO -> ?*Si-S(e) transitions.
REACTIONS OF DIAZOALKANES WITH UNSATURATED COMPOUNDS. 6. CATALYTIC CYCLOPROPANATION OF UNSATURATED HYDROCARBONS AND THEIR DERIVATIVES WITH DIAZOMETHANE
Dzhemilev, U. M.,Dokichev, V. A.,Sultanov, S. Z.,Khusnutdinov, R. I.,Tomilov, Yu. V.,et al.
, p. 1707 - 1714 (2007/10/02)
A systematic study has been conducted of the catalytic reaction of diazomethane with cyclic and polycyclic unsaturated hydrocarbons, conjugated dienes, as well as with a series of functionalized unsaturated conpounds.The feasibility of using transition metal, nontransition metal, and rare earth metal compounds of, for example, Co, Ni, Zr, Rh, and Dy, has been demonstrated for the first time.It has also been established that Pd(acac)2 has very high activity as a catalyst for the cyclopropanation of terminal and endocyclic double bonds by diazomethane, and that its activity is reduced upon the introduction of n-donor ligands or in the presence of strong polar solvents.
Process for cyclizing upsilon-chlorocarboxylic acids
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, (2008/06/13)
γ-chlorocarboxylic acid methyl or ethyl esters are cyclized to the corresponding cyclopropane carboxylic acid esters by employing the sodium or potassium alcoholate of methanol or ethanol in the presence of the same alcohol at a temperature above the boiling point of the alcohol employed.
Cyclopropanation of α,β-Unsaturated Carbonyl Compounds and Nitriles with Diazo Compounds. The nature of the Involvement of Transition-Metal Promoters
Doyle, Michael P.,Dorow, Roberta L.,Tamblyn, William H.
, p. 4059 - 4068 (2007/10/02)
In the presence of molybdenum hexacarbonyl or molybdenum(II) acetate, ethyl diazoacetate and α-diazoacetophenone react with α,β-unsaturated carbonyl compounds and nitriles to form derivative cyclopropane and vinyl CH insertion products.In the absence of these promoters or in the presence of catalytic amounts of pyridine, 2-pyrazolines are the major or sole reaction products.Kinetic investigations for reactions between ethyl diazoacetate and α,β-unsaturated esters and nitriles in the presence of Mo(CO)6, Mo2(OAc)4, or pyridine demonstrate the absence of any significant influence by these molybdenum promoters or pyridine on the rates and activation parameters for ethyl diazoacetate decomposition.Representative 1-pyrazolines have been synthesized and observed to undergo dinitrogen extrusion without apparent influence by molybdenum promoters.The composite results suggest that these molybdenum promoted reactions occur by dipolar cycloaddition of diazocarbonyl compounds to α,β-unsaturated systems and that the derivative 1-pyrazoline intermediates undergo dinitrogen extrusion to form the observed cyclopropane and vinyl CH insertion products.Molybdenum promoters function to inhibit competitive tautomerization of the initially formed cycloaddition products.The relative effectiveness of a broad selection of transition-metal compounds in directing reactions between ethyl diazoacetate and α,β-unsaturated esters and nitriles to cyclopropane products is described.The cycloaddition / dinitrogen extrusion pathway is presented as a viable mechanism for cyclopropanation of α,β-unsaturated systems by diazo compounds, even for reactions performed in the presence of traditional cyclopropanation catalysts.
Conformational Analysis of the Cyclopropylacyl, Oxiranylacyl, and Aziridinylacyl Radicals by Electron Spin Resonance Spectroscopy
Davies, Alwyn G.,Sutcliffe, Roger
, p. 1483 - 1488 (2007/10/02)
A series of ring-substituted cyclopropylacyl, oxiran-2-ylacyl, and aziridin-2-ylacyl radicals have been prepared principally by the reaction of photolytically generated t-butoxyl radicals with the corresponding aldehydes.The e.s.r. spectra show that the cyclopropylacyl ?-radicals exist in s-cis- and s-trans-conformations of approximately equal stability, in which the plane of the acyl group bisects the ring (as it does in the parent aldehyde), and simulation of the spectra through the region of intermediate rates of exchange show that the barrier to rotation is ca. 17.5 kJ*mol-1.The behaviour of the trans-2-ethoxycarbonylcyclopropylacyl and 2,2-dimethylcyclopropylacyl radicals is similar.The oxiranylacyl and trans-3-methyloxiranylacyl radicals exist in the same two conformations with a rather lower barrier, and the N-alkylaziridinylacyl radicals appear to have a lower barrier still.
