1.4- DIMETHYLCYCLOHEXANE-trans

Wedge and dash drawings fail to show conformation and it s important to remember that the rings of cis and trans 1 2 dimethylcyclohexane exist m a chair conformation This... 

CIS 1 2 Dimethylcyclohexane trans 1 2 Dimethylcyclohexane Axial-equatorial Diequatorial (1248 3) (1246 8) (1 5) trans... 

A reaction that introduces a second chirality center into a starting material that already has one need not produce equal quantities of two possible diastereomers Con sider catalytic hydrogenation of 2 methyl(methylene)cyclohexane As you might expect both CIS and trans 1 2 dimethylcyclohexane are formed... 

No The major product as 1 2 dimethylcyclohexane is less stable than the minor product trans 1 2 dimethylcyclohexane... 

Figure 5.20 trans- 1,2-Dimethylcyclohexane has no plane of symmetry and exists as a pair of enantiomers (a and b). [Notice that we have written the most stable conformations for (a) and (b). A ring flip of either (a) or (b) would cause both methyl groups to become axial.]... 

The triethylsilane/trifluoroacetic acid reagent system reduces alkenes to alkanes in poor to excellent yields depending largely on the ability of the alkene to form carbocations upon protonation. Under these conditions the more substituted olefins are reduced in better yields and styrene double bonds are reduced in high yields.127,202,207,221-228 The reduction of 1,2-dimethylcyclohexene with this reagent gives a mixture of cis- and trans- 1,2-dimethylcyclohexane.229 The formation of the trifluoroacetate esters is a side reaction.205,230... 

DIMETHYLCYCLOHEXANE cis-1,2-DIMETHYLCYCLOHEXANE trans-1,2-DIMETHYLCYCLOHEXANE cis-1,3-DIMETHYLCYCLOHEXANE trans-1,3-DIMETHYLCYCLOHEXANE c i s-1,4-DIMETHYLCYCLOHEXANE trans-1,4-DIMETHYLCYCL0HEXANE ETHYLCYCLOHEXANE 2-ETHYL-1-HEXENE... 

Chemical/Physical. Complete combustion in air yields carbon dioxide and water vapor, trans-1,2-Dimethylcyclohexane will not hydrolyze because it has no hydrolyzable functional group. 

Like the 1,4-dimethyl derivatives, trans-1,2-dimethylcyclohexane has a lower heat of combustion (see Table 3.2) and is more stable than cis-1,2-dimethylcyclohexane. The cis stereoisomer has two chair conformations of equal energy, each containing one axial and one equatorial methyl group. 

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