Advices For Studying Organic Chemistry

H CH 3 (a)

C H

CH 3

H 3 C

H 3 C

Table 4.9 Conformations of Dimethylcyclohexanes

Compound Cis Isomer Trans Isomer

1,2-Dimethyl a,e or e,a e,e or a,a

1,3-Dimethyl e,e or a,a a,e or e,a

1,4-Dimethyl a,e or e,a e,e or a,a

4.15 BICYCLIC AND POLYCYCLIC ALKANES

1. Decalin (bicyclo[4.4.0]decane):

H 2 C

H 2 C

CH

2

C

C

H 2

C

CH

2

CH 2

CH 2

H 2

H C

H

1 2 3

8 7 6 5 4

(^910) or
Decalin (bicyclo[4.4.0]decane)
(carbon atoms 1 and 6 are bridgehead carbon atoms)

1. Decalin shows cis-trans isomerism:
   H
   H
   H
   H
   cis-Decalin trans-Decalin