Exercise 4 | Cycloalkanes

Draw the cis and the trans isomer of 1-(tert-butyl)-4-fluorocyclohexane.

For each isomer, draw the two chair conformations and circle the most stable conformation.

What is the most stable isomer?

The tert-butyl substituent is bulkier than the fluoro substituent:
for each isomer the most stable conformation is that with the tert-butyl substituent in the equatorial position.

The most stable isomer is that with the two substituents in the equatorial position: the trans isomer is the most stable.