If we have a ketone with FOUR carbon atoms, where can the carbonyl group be placed?

1 Answer
Oct 25, 2016

Answer:

Clearly, the carbonyl group is at #C2# in butanone.

Explanation:

For a four carbon chain to be a ketone, the only position for the carbonyl is an #C2#, i.e. to give #H_3C-C(=O)CH_2CH_3#. Substitution at #C1# gives the aldehyde, #H(O=)C-CH_2CH_2CH_3#.

Of course, for cyclohexanone, or cyclobutanone, the oxo group could be at #C1#, but these are special circumstances.