Advices For Studying Organic Chemistry

i) When viewed along any C—C bond, the atoms are seen to be perfectly

staggered.

ii) The hydrogen atoms at opposite corners (C1 and C4) of the cyclohexane ring

are maximally separated.

H

H

H

H

H

H

CH 2

CH 2

1

5 6 2 3

4

H H

H

H

H

H

(a) (b)
Figure 4.13 (a) A Newman projection of the chair conformation of cyclohexane.
(Comparisons with an actual molecular model will make this
formulation clearer and will show that similar staggered arrangements
are seen when other carbon-carbon bonds are chosen for sighting.) (b)
Illustration of large separation between hydrogen atoms at opposite
corners of the ring (designated C1 and C4) when the ring is in the chair
conformation.

2. Boat conformation of cyclohexane:
   
   
   1. Boat conformation of cyclohexane is free of angle strain.
   
   
   2. Boat cyclohexane has torsional strain and flagpole interaction.
      i) When viewed along the C—C bond on either side, the atoms are found to be
      eclipsed ⇒ considerable torsional strain.
      ii) The hydrogen atoms at opposite corners (C1 and C4) of the cyclohexane ring
      are close enough to cause van der Waals repulsion ⇒ flagpole interaction.