3.4- Dimethyl-cis-3-hexene

C8H16 1-methyl-trans-3-ethylcyclopentane 2613-65-2 165.15 11.482 2 14948 C8H16 3,4-dimethyl-cis-2-hexene 19550-81-3 145.38 11.845 2... 

Ozonolysis of Tetramethylene and cis-3,4-Dimethyl- 3 -hexene. A solution of tetramethylethylene (0.503 gram, 5.98 mmoles) and cis-3,4-dimethyl-3-hexene (0.692 gram, 6.17 mmoles) in 20 ml pentane was ozonized to 63% theoretical yield at —40°C. The product mixture was analyzed by GPC using an 8-ft 10% XF-1150 column at 85°C and a flow rate of 150 ml/minute. The mixture contained 25 mg acetone diperoxide, 36.7 mg l,l,4-trimethyl-4-ethyl-2,3,5,6-tetraoxacyclohexane, and 23.2 mg methyl ethyl ketone diperoxide as determined by GPC using an internal standard. Total yield of diperoxides was 14%. The diperoxides were identified by comparing mp, infrared, NMR, and GPC data with those of authentic samples. 

Ozonolysis of cis-3,4-Dimethyl-3 -hexene. A solution of cis-3,4-di-methyl-3-hexene (98% pure, Chemical Samples Co.) (1.12 grams, 10 mmoles) in 50 ml pentane was ozonized at — 62°C until the blue color of excess ozone was evident. A nitrogen stream was used to purge the solution of excess ozone. Pentane was then carefully distilled off at atmospheric pressure. A water aspirator (20 mm Hg) was then used to remove the ketone product. Treatment of this material with 10 ml of an 0.1 M solution of 2,4-dinitrophenylhydrazine gave 2.33 grams of crude 2,4-dinitrophenylhydrazone. The crude product was recrystallized and identified as the 2,4-dinitrophenylhydrazone of methyl ethyl ketone, mp 115-116°C. Yield of the ketone was 92% based on olefin used. 

By choosing olefins of comparable reactivity towards ozone this difficulty can be avoided. When approximately equimolar amounts of 7 and cis-3,4-dimethyl-3-hexene, 8, were ozonized together all three predicted diperoxides were obtained—i.e., acetone diperoxide, 9, the cross diperoxide, l,l,4-trimethyl-4-ethyl-2,3,5,6-tetraoxacyclohexane, 10, and methyl ethyl ketone diperoxide, 11. 

It was now important to examine the question of a possible stereochemical influence on diperoxide formation. We have approached this problem initially by ozonizing olefins of type 2. When either cis- or trans-3,4-dimethyl-3-hexene are ozonized, presumably a single stereoisomeric pair of diperoxides can be formed. In fact, this case is complicated by the possibility of two trans-diperoxide conformers being produced. The cis-diperoxide conformers are identical. Ozonolysis of cis-3,4-dimethyl-3-hexene, 8, for example, could give the diperoxides, cis-l,3-dimethyl-l,3-diethyl-2,3,5,6-tetraoxacyclohexane, 11a, and rans-l,3-dimethyl-l,3-di-ethyl-2,3,5,6-tetraoxacyclohexane, lib, with the latter capable of existing as conformers lib and lib with trans-diaxial methyl and trans-diaxial ethyl substituents, respectively. 

Over 300 diol metabolites are known.8 Several diols and some secondary synthons derived from them have recently become commercially available Eastman Fine Chemicals, Genencor (1 S-cis)-3-Chloro-3,5-cyclohexadiene-1,2-diol, (1 S-cis)-3-bromo-3,5-cyclohexadiene-1,2-diol, (1 S-cis)-3-iodo-3,5-cyclohexadiene-1,2-diol, (5S-cis)-5,6-dihydroxy-1,3-cyclohexadiene-1 -carbonitrile, cis-2R,3S-2,3-dihydroxy-2,3-dihydrobenzonitrile acetonide, (1R-cis)-1,2-dihydro-1,2-naphthalenediol, (1R-cis)-1,2,3,4-tetrahydro-1,2-naphthalenediol, (4S-trans)-4,5-dihydroxy-3-oxo-1 -cyclo-hexene-1-carboxylic acid, furo[3,4-d]-1,3-dioxol-4(3aH)-1 -dihydro-6-hydroxy-2,2-dimethyl-[3aR-(3aa,6aa)]. 

Figure 6. The reciprocals of the primary methyl radical quantum yields in the 184.9 nm photolysis of 2,3(0) and 3,3-dimethyl-l-butene ( ), cis-3-hexene ( ), and 4-methyl-cis-2-pentene ( ) versus the pressure. From Ref. 67.

The most common method for specifying the configuration in alkenes uses the prefixes cis and trans. There is no doubt which isomers are intended by the names trans-3-hexene and ds-3-hexene. For more complex alkenes, the orientation of the atoms of the parent chain determines whether the alkene is cis or trans. On the right is a structural formula for the cis isomer of 3,4-dimethyl-2-pentene. In this example, carbon atoms of the main chain (carbons 1 and 4) are on the same side of the double bond therefore, this alkene is cis. 

Rank the following compounds in order from most stable to least stable trans-3-hsxsns, cis-3-hexene, cM-2,5-dimethyl-3-hexene, cw-3,4-dimethyl-3-hexene... 

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