Question

$IUPAC$ name of the following compound

is

• A. 1-hydroxycyclohex-4-en-3-one
• B. 1-hydroxycyclohex-3-en-5-one
• C. 3-hydroxycyclohex-5-en-1-one
• D. 5-hydroxycyclohex-2-en-1-one

Answer 1

Answer: (D)

Principal functional group is ketone
$\therefore C_1$ is carbonyl carbon atom.
Locants for hydroxyl groups and double bonds are 5 and 2, which are preferred over 3 and 5, since the lower number at first difference (2 compared to 3) is preferred.
Hence, the $IUPAC$ name of given compound is 5-hydroxycyclohex-2-en- 1-one