BackThe most stable form of glucose (blood sugar) is a six-membered ring in a chair conformation with its five substituents all in equatorial positions. Draw the most stable conformer of glucose by putting the OH groups and hydrogens on the appropriate bonds in the structure on the right.
The most stable form of the common sugar glucose contains a six-membered ring in the chair conformation with all the substituents equatorial. Draw this most stable conformation of glucose.
For each pair of conformations shown, choose which is most stable. If both are equally stable, then write 'no difference.' [If both conformations have the same number of axial substituents, choose the one with the smallest axial substituents.]
(g)
For each of the following compounds, determine whether the cis isomer or the trans isomer is more stable.
a.
b.
c.
For each structure shown, draw the two chair conformations and choose which is most stable. Be sure that your second chair is the flipped version of the first. [Make sure that wedged substituents are up in the chair, regardless of whether up is equatorial or axial.]
(g)
Draw the most stable conformation of
a. cis-1-tert-butyl-3-ethylcyclohexane.
Draw the two chair conformers for each of the following and indicate which conformer is more stable:
f. cis-1-ethyl-4-isopropylcyclohexane
Draw the LEAST STABLE conformation of trans-1-tert-butyl-3-neopentylcyclohexane.
Which compound is more stable: cis-1-ethyl-2-methylcyclohexane or trans-1-ethyl-2-methylcyclohexane?
Draw the MOST STABLE conformation of cis-1-tert-butyl-4-methylcyclohexane.
In contrast to ethane and other alkanes studied in this chapter, there is no free rotation around any bonds in cyclopentane (shown below). Why?
Draw the most stable conformation of
c. cis-1-tert-butyl-4-isopropylcyclohexane.
Draw the most stable conformer of the following molecule. (A solid wedge points out of the plane of the paper toward the viewer. A hatched wedge points back from the plane of the paper away from the viewer.)
Draw the most stable conformation of
a. ethylcyclohexane.
Draw the most stable conformation of
b. 3-isopropyl-1,1-dimethylcyclohexane.