Question

Which form of cis-1, 4-cyclohexane diol is most stable?

• A.
• B.
• C.
• D.

Answer 1

The correct option is B

In conformer (b), there will be a strong intramolecular hydrogen bonding. In cyclohexane boat form 1, 4 interaction is know as Flagpole interaction which makes it unstable. But in this case, $-OH$ groups are present instead of hydrogen and there will be a strong hydrogen bonding and no flagpole interaction. Hence, diaxial boat form is more stable.

In conformer (a), there will be flagpole interaction and it is less stable.

In conformer (c), the $OH$ group in 1, 4 axial position so it is less stable.

In conformer (d), both $OH$ groups are in equatorial position. But there is no hydrogen bonding. So, the stable comformer in (b).