See image — IUPAC and Nomenclature Chemistry Question

💡 Solution & Explanation

Step 1: Identify the parent chain. The compound is a cyclohexane ring, so the parent name is 'cyclohexane.' Step 2: Identify the principal characteristic group. The hydroxyl group (-OH) is the principal characteristic group, so the suffix '-ol' is used, giving 'cyclohexanol.' Step 3: Identify all substituents. The ring bears: an -OH group, a -Cl (chloro) substituent, a -Br (bromo) substituent, and an exocyclic double bond (=CH2, methylidene group). Step 4: Number the ring to give the principal characteristic group (-OH) the lowest possible locant. Assign C1 to the carbon bearing -OH. Step 5: Proceed around the ring to assign locants to other substituents with the lowest set of locants. Going in the direction that gives lower numbers: C1 = OH, C2 = Cl, C3 = Br, C5 = =CH2 (methylidene). The set {1,2,3,5} is lower than the alternative direction {1,2,3,5} checked both ways confirms this numbering. Step 6: Name the exocyclic =CH2 group. An exocyclic double bond where the ring carbon bears =CH2 is named as 'methylidene' (or 'methylene') substituent, indicated by the suffix '-idenecyclohexanol' with the locant 5. Step 7: Assemble the full name. List substituents alphabetically with locants: 3-bromo, 2-chloro, 5-methylidene, parent = cyclohexanol. Full name: 3-bromo-2-chloro-5-methylidenecyclohexanol. Step 8: Why other orderings fail. Any other numbering would give a higher locant set for the principal characteristic group or substituents, violating IUPAC rules for lowest locant set. Therefore, the correct answer is 3-bromo-2-chloro-5-methylidenecyclohexanol.