How many gauche interactions are present in the trans 1/2-Dimethylcyclohexane a a conformer between the methyl groups and between the methyl groups and the ring?
four gauche
The diaxial conformer is equivalent to two axial methylcyclohexanes…. one above the ring; one below. Thus there are four gauche butane interactions.
What is the position of 2 methyl group in trans 1 to dimethyl cyclohexane?
equatorial position
The more stable chair conformation of trans-1,2-dimethylcyclohexane has the two methyl groups in the equatorial position.
Which is the most stable conformation of cis 1/2-Dimethylcyclohexane?
trans-1
The trans-1,2-dimethylcyclohexane has the most stable conformer, so it is the more stable isomer….Disubstituted Cyclohexanes: The Relative Stability of cis and trans Isomers.
| substitution type | most stable isomer |
|---|---|
| 1,2-disubstituted cyclohexanes | trans |
Which is the most stable conformation?
staggered conformation
hydrocarbons. …with respect to the other—the eclipsed conformation is the least stable, and the staggered conformation is the most stable. The eclipsed conformation is said to suffer torsional strain because of repulsive forces between electron pairs in the C―H bonds of adjacent carbons.
Is axial more stable than Equatorial?
A conformation in which both substituents are equatorial will always be more stable than a conformation with both groups axial.
Is 1 3 Dimethylcyclohexane a trans or cis?
The preferred chair has both methyl groups equatorial, which minimises 1,3-diaxial repulsions. In the 1,3-disubstituted case this is possible only for the cis-isomer, which is 7 kJ/mol more stable than the trans-isomer (in the 1,3-trans isomer one of the methyl groups must be axial).
Why is a 1/3 cis disubstituted cyclohexane?
Cis and trans stereoisomers of 1,3-dimethylcyclohexane The other conformer has both methyl groups in equatorial positions thus creating no 1,3-diaxial interaction. Because the methyl groups are not on adjacent carbons in the cyclohexane rings gauche interactions are not possible.
What is the most stable form of 1/3-Dimethylcyclohexane?
Because large groups prefer to be equatorial, the most stable conformer for cis-1,3-dimethylcyclohexane is the diequatorial conformer, shown here. The diaxial conformer would be higher in energy.
Why is it called 1/3-Diaxial?
The energy difference between the two conformations comes from strain, called 1,3-diaxial interactions, created when the axial methyl group experiences steric crowding with the two axial hydrogens located on the same side of the cyclohexane ring.
What is the gauche butane interaction in trans-1, 2-cyclohexane?
trans-1,2-dimethylcyclohexane has a gauche butane interaction (redand bluecarbon atoms) between the two methyl groups. This situation does not arise in 1,3- and 1,4-disubstituted chair cyclohexanes. View the gauche butane interaction (0.9 kcal/mol) as a Newman
Is the gauche butane interaction a Newman projection?
View the gauche butane interaction (0.9 kcal/mol) as a Newman projection. The other chair conformation of trans-1,2-dimethylcyclohexane has the two methyl groups axial. Recall that a chair-chair conformational inversion interchanges equatorial and axial substituents.
Is the chair conformer of methylcyclohexane gauche or gauche?
Contrary to the case of methylcyclohexane, which has no interactions in the chair conformation having an equatorial methyl group, the diequatorial conformer of trans-1,2-dimethylcyclohexane has a gauche butane interaction (red and blue carbon atoms) between the two methyl groups.
Which is the diequatorial conformer of Trans 1, 2 dimethylcyclohexane?
Contrary to the case of methylcyclohexane, which has no interactions in the chair conformation having an equatorial methyl group, the diequatorial conformer of trans-1,2-dimethylcyclohexane has a gauche butane interaction (redand bluecarbon atoms) between the two methyl groups.
