Question

What are the isomers of `C_5H_12O`?

Answer 1

Here's how many I get:

1. I moved methyl groups (`1^@` alcohol to begin with).
2. I moved the alcohol group by 1 and then moved methyl groups again (asymmetrical `2^@` alcohol to begin with).
3. I moved the alcohol group again and then moved methyl groups again (symmetrical `2^@` alcohol to begin with).
4. I moved methyl groups in an ether.
5. I moved the oxygen to the final spot possible, since when incorporating flip symmetry we get the same ether if the oxygen is in the place of carbons 2 vs. 4 or 3 vs. 5. Then I moved methyl groups again.

Each squiggle bond indicates a pair of enantiomers. So in total I found `20` isomers, including stereoisomers.