Buten 4- -cyclohexen

A dry 5(X)-mI flask equipped with a thermometer, pressure-equalizing dropping funnel, and magnetic stirrer is flushed with nitrogen and then maintained under a static pressure of the gas. The flask is charged with 50 ml of tetrahydrofuran and 13.3 ml (0.15 mole) of cyclopentene, and then is cooled in an ice bath. Conversion to tricyclo-pentylborane is achieved by dropwise addition of 25 ml of a 1 M solution of diborane (0.15 mole of hydride see Chapter 4, Section 1 for preparation) in tetrahydrofuran. The solution is stirred for 1 hour at 25° and again cooled in an ice bath, and 25 ml of dry t-butyl alcohol is added, followed by 5.5 ml (0.05 mole) of ethyl bromoacetate. Potassium t-butoxide in /-butyl alcohol (50 ml of a 1 M solution) is added over a period of 10 minutes. There is an immediate precipitation of potassium bromide. The reaction mixture is filtered from the potassium bromide and distilled. Ethyl cyclopentylacetate, bp 101730 mm, 1.4398, is obtained in about 75% yield. Similarly, the reaction can be applied to a variety of olefins including 2-butene, cyclohexene, and norbornene. 

It appears that oxiranes known to give predominantly a-deprotonation in basic media (cyclopentene, cyclooctene and exo-norbomene oxide) are also the more strained (Table 1 entries 3, 6, 7). On the other hand, oxiranes that give mainly -deprotonation (butene, cyclohexene oxide) have lower strain energies and higher a-anion stabilities (Table 1 ... 

On treatment of phosphine with I-butene, cyclohexene, allyl alcohol, allylamine or allyl chloride, the corresponding primary, secondary and tertiary organophosphines are obtained in yields ranging from 2 to 67%. The reaction between phosphine and 1-butene is, among others, used for the industrial preparation of tributylphosphine. ... 

All this was later put on a sound basis as a result of more precise measurements of rate constants and of activation energies. However, it did not require precise measurements to predict which chlorinated hydrocarbons would decompose by a radical chain mechanism and which by the unimolecular mechanism. Clearly, if the chlorinated hydrocarbon, or the product from the pyrolysis of the chlorinated hydrocarbon reacted with chlorine atoms to break the chain then the chain mechanism would not exist. Such chlorinated hydrocarbons would decompose by the unimolecular mechanism. Mono-chlorinated derivatives of propane, butane, cyclohexane, etc. would afford propylene, butenes, cyclohexene, etc. All these olefins are inhibitors of chlorine radical chain reactions because of the attack of chlorine atoms at their allylic positions to give the corresponding stabilized allylic radicals which do not carry the chain. 

Bei Umsetzungen von Phosphin mit 1-Buten, Cyclohexen, Allyl-alkohol, Allylamin und Allylchlorid zu entsprechenden primaren, sekun-daren und tertiaren Organophosphinen wurden Ausbeuten von 2—67% erzielt. Die Reaktion zwischen Phosphin und I-Buten wird u. a. fur die industrielle Erzeugung von Tributylphosphin beniitzt 198>. 

Because of their rapid breakdown process, chlorinated solvents are almost invariably sold containing a stabilizer. Dichloromethane has 25 ppm amylene (2-methyl-2-butene), cyclohexene, 400-600 ppm methanol, or a methanol/amylene blend as stabilizer. These alkenes act as chemical sinks that react with hydrochloric acid. Cyclohexane has also been used as a preservative but its efficacy is questionable. 

The kinetics of the formation of nitration products in reactions of various alkenes with NO + in CCl, CH Cl and hexane were investigated by stopped-flow spectroscopy [62]. The rates of reactions of 2,3-dimethyl-2-butene, cyclohexene, and 1-hexene were measured over a wide range of NO concentrations, from <0.1 mM to 760 mM. For all of these substrates, the order in NO is 2 at high NO and decreases to 1 as the concentration of NO decreases. These data indicate the presence of at least two reaction pathways. One involves the diamagnetic dimer in an addition mechanism (Equation 5.117), and the other involves monomer NO (Equation 5.116). The reaction of the monomer NO proceeds also through abstraction of allylic hydrogen atoms. 

The water-soluble rhodium complex [Rh(p.-pz)(CO)(TPPTS)]2 (pz = pyrazolate) was used as catalyst precursor during the two-phase catalytic hydroformylation of different olefins at 100 °C, 50 bar (CO H2 = 1 1), 600 rpm, and substrate catalyst ratio of 100 1. A reaction order- 1-hexene > styrene > allylbenzene > 2,3-dimethyl-1-butene > cyclohexene-was found. The experiments also showed that the binuclear catalyst precursor was resistant to possible sulfur poisons [108]. 

A similar procedure has been employed to silylate the dianion of 3-methyl-3-buten-2-ol (67% yield).In systems where such internal activation is not possible (e.g. 2-raethyl-2-cyclohexen-l-o1), dianion formation can be performed in hexane to give a 75% yield of the corresponding disilyl compound. 

Among the cases in which this type of kinetics have been observed are the addition of hydrogen chloride to 2-methyl-1-butene, 2-methyl-2-butene, 1-mefliylcyclopentene, and cyclohexene. The addition of hydrogen bromide to cyclopentene also follows a third-order rate expression. The transition state associated with the third-order rate expression involves proton transfer to the alkene from one hydrogen halide molecule and capture of the halide ion from the second ... 

Perhaps the most striking difference between conjugated and nonconjugated dienes is that conjugated dienes undergo an addition reaction with alkenes to yield substituted cyclohexene products. For example, 1,3-butadiene and 3-buten-2-one give 3-cycIohexenyl methyl ketone. 

This is the same case with which in Eqs. (2)-(4) we demonstrated the elimination of the time variable, and it may occur in practice when all the reactions of the system are taking place on the same number of identical active centers. Wei and Prater and their co-workers applied this method with success to the treatment of experimental data on the reversible isomerization reactions of n-butenes and xylenes on alumina or on silica-alumina, proceeding according to a triangular network (28, 31). The problems of more complicated catalytic kinetics were treated by Smith and Prater (32) who demonstrated the difficulties arising in an attempt at a complete solution of the kinetics of the cyclohexane-cyclohexene-benzene interconversion on Pt/Al203 catalyst, including adsorption-desorption steps. 

The most radiation-stable poly(olefin sulfone) is polyethylene sulfone) and the most radiation-sensitive is poly(cyclohexene sulfone). In the case of poly(3-methyl-l-butene sulfone) there is very much isomerization of the olefin formed by radiolysis and only 58.5% of the olefin formed is 3-methyl-l-butene. The main isomerization product is 2-methyl-2-butene (37.3% of the olefin). Similar isomerization, though to a smaller extent, occurs in poly(l-butene sulfone) where about 10% of 2-butene is formed. The formation of the olefin isomer may occur partly by radiation-induced isomerization of the initial olefin, but studies with added scavengers73 do not support this as the major source of the isomers. The presence of a cation scavenger, triethylamine, eliminates the formation of the isomer of the parent olefin in both cases of poly(l-butene sulfone) and poly(3-methyl-1-butene sulfone)73 indicating that the isomerization of the olefin occurred mainly by a cationic mechanism, as suggested previously72. 

Methyl-buten-(3)-in-(l) liefert mit Dicyclohexyl-boran und Deuterolyse 3-Methyl-1 -deutero-butadien-(trans-1,3) (92% d.Th.) bzw. 1-Athinyl-cyclohexen trans-2-Deute-ro-1 -[cyclohexen-(l)-yl]-athylen (87% d.Th.)3. Die Reduktionen sind auch mit [2,3-Di-methyl-butyl-(2)]-boran durchfiihrbar. 

Cyclohexanon Mesityloxid I - Acetyl-cyclohexen 3-Oxo- l-phenyl-buten-( 1)... 

The stereochemistry of addition of hydrogen halides to alkenes depends on the structure of the alkene and also on the reaction conditions. Addition of hydrogen bromide to cyclohexene and to E- and Z-2-butene is anti.6 The addition of hydrogen chloride to 1 -methylcyclopentene is entirely anti when carried out at 25° C in nitromethane.7... 

Copper(II) triflate has also been used for the carbenoid cyclopropanation reaction of simple olefins like cyclohexene, 2-methylpropene, cis- or rran.y-2-butene and norbomene with vinyldiazomethane 2 26,27). Although the yields were low (20-38 %), this catalyst is far superior to other copper salts and chelates except for copper(II) hexafluoroacetylaeetonate [Cu(hfacac)2], which exhibits similar efficiency. However, highly nucleophilic vinyl ethers, such as dihydropyran and dihydrofuran cannot be cyclopropanated as they rapidly polymerize on contact with Cu(OTf)2. With these substrates, copper(II) trifluoroacetate or copper(II) hexafluoroacetylaeetonate have to be used. The vinylcyclopropanation is stereospecific with cis- and rra s-2-butene. The 7-vinylbicyclo[4.1.0]heptanes formed from cyclohexene are obtained with the same exo/endo ratio in both the Cu(OTf)2 and Cu(hfacac)2 catalyzed reaction. The... 

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