Advices For Studying Organic Chemistry

(CH 2 )n (CH 2 )n

A catenane (n^ ≥^18 )

4.13 SUBSTITUTED CYCLOHEXANES:

AXIAL AND EQUATORIAL HYDROGEN ATOMS

1. The six-membered ring is the most common ring found among nature’s organic
   molecules.


2. The chair conformation of cyclohexane is the most stable one and that it is the
   predominant conformation of the molecules in a sample of cyclohexane.

1. Equatorial hydrogens: the hydrogen atoms lie around the perimeter of the ring
   of carbon atoms.


2. Axial hydrogens: the hydrogen atoms orient in a direction that is generally
   perpendicular to the average of the ring of carbon atoms.

H

H

H

H

H

H

H

H H

H

(^1) H H
(^234)
6 5
Figure 4.18 The chair conformation of cyclohexane. The axial hydrogen atoms
are shown in color.
Axial bond up
Vertex of ring up
Axial bond up
Vertex of ring up
(a) (b)
Figure 4.19 (a) Sets of parallel lines that constitute the ring and equatorial C–H
bonds of the chair conformation. (b) The axial bonds are all vertical.
When the vertex of the ring points up, the axial bond is up and vice
versa.
3) Ring flip: