See image — IUPAC and Nomenclature Chemistry Question

💡 Solution & Explanation

Step 1: Identify the parent ring. The core structure is a six-membered carbocycle (cyclohexane/cyclohexene). There is one double bond in the ring, making it a cyclohexene. Step 2: Identify and number the substituents on the cyclohexene ring. The principal characteristic group is the carboxylic acid (–CO2H), which receives the lowest possible locant. Assign C1 to the carbon bearing –CO2H. Moving around the ring, C2 bears a chlorine atom. The double bond exists between C2 and C3 (or equivalently, choosing numbering so the double bond is between C2 and C3 gives 'cyclohex-2-ene'). C4 (or C5 depending on direction) bears the cyclobutyl substituent. Proper IUPAC numbering to give lowest locants places: C1 = CO2H, C2 = Cl and one end of double bond, C3 = other end of double bond, C4 = cyclobutyl attachment, giving the prefix cyclohex-2-ene. Step 3: Name the substituent on C4. The attached ring is a cyclobutane ring with a ketone (oxo, C=O) at the 3-position relative to the point of ring attachment, giving '3-oxocyclobutyl'. Step 4: Assemble the full IUPAC name. Parent chain: cyclohex-2-ene-1-carboxylic acid. Substituents: 6-chloro (the Cl is on C6 when carboxylic acid is C1 and double bond is between C2 and C3, numbering so that Cl gets the lower locant consistent with the double bond position) and 4-(3-oxocyclobutyl). Combining: 6-chloro-4-(3-oxocyclobutyl)cyclohex-2-ene-1-carboxylic acid, which matches the given answer written as 6-chloro-4-(3-oxo cyclobutyl)cyclohex-2-ene carboxylic acid. Step 5: Verify locants. With C1 = CO2H, the double bond between C2–C3, Cl on C6 (adjacent to C1 on the other side), and the cyclobutyl group on C4, the locant set {1,2,4,6} is the lowest possible set, confirming the numbering is correct. Therefore, the correct answer is 6-chloro-4-(3-oxo cyclobutyl)cyclohex-2-ene carboxylic acid.