Naming/ Drawing Exercises

2,2,6,7-tetramethylnonane
1
2
3…
Careful with the parent chain!!! Don’t be fooled by the seeming 1-tert-butyl group LOL.

3-ethyl-4-isopropyl-2,5dimethylheptane
7
3
2
1
The trick here is to remember WE PREFER HAVING MORE BRANCHING when we find 2 or more possible parent chains.

3,3,6-triethyl-6-methyloctane
3
2
1
Since we can’t reduce numbering either way (3,3,6,6) WE NOW CHOOSE NUMBERING
WITH ALPHABETICAL PRIORITY… smaller numbers for ‘e’ in ethyl than ‘m’ for methyl.

1,1,2-triethyl-2-methylcyclopentane
Since we can’t reduce numbering either way (1,2 or 2,1) WE NOW CHOOSE NUMBERING
WITH ALPHABETICAL PRIORITY… smaller numbers for ‘e’ in ethyl than ‘m’ for methyl.

1-ethyl-1,2,4-trimethyl-4-
(propan-2-yl)cyclohexane or
1-ethyl-4-isopropyl-1,2,4trimethylcyclohexane

Most stable form?
H

Most stable form?
ETHYL Too bulky for axial!
H
ISOPROPYL also too bulky

More Stable?
H
After a RING FLIP, the bulkier groups are now along the
EQUATORIAL POSITION, with less steric strain, because the bulky groups are all pointing out of the ring, and not “blocking” other groups/ having repulsions with other electron clouds.

The same or different?
H
H