A twist$-$boat conformation may be obtained by slightly twisting carbon atoms $2$ and $5$ while

keeping atoms $1$ and $4$ above or beneath the other atoms. Twisting too far will lead to the chair

conformation.

twist$-$boat contormation

Note how carbons $2,3,5,$ and $6$ are no longer coplanar.

a$.$ Compare the number of eclipsing interactions in the twist$-$boat and boat conformations.

Which one has more?

b$.$ Rank the chair, boat, and twist$-$boat conformations in order of increasing stability.

c$.$ Which one of these will have the most negative energy value?