See image — IUPAC and Nomenclature Chemistry Question

💡 Solution & Explanation

Step 1 (Identify the parent chain/ring): The compound is a cyclohexane ring bearing three substituents: an aldehyde group (CHO), a bromine atom (Br), and a methyl group (CH3). When an aldehyde is directly attached to a ring, the ring carbon bearing the CHO is the principal characteristic group, and the compound is named as a cycloalkane-carbaldehyde. The parent name is therefore cyclohexanecarbaldehyde. Step 2 (Number the ring): The carbon bearing the CHO group is automatically C1 (the point of attachment for the principal characteristic group suffix '-carbaldehyde'). Numbering proceeds around the ring to give the substituents the lowest possible locants. Step 3 (Assign locants to substituents): Going in one direction from C1, Br is on the adjacent carbon (C2) and methyl is two carbons away (C3). Going in the other direction, methyl is on the adjacent carbon (C2) and Br is two carbons away (C3). Applying the lowest-set-of-locants rule: the set {2,3} is the same in both directions, so we apply the rule of first point of difference alphabetically — 'b' (bromo) comes before 'm' (methyl), so Br should receive the lower locant. Assign C2 = Br and C6 = methyl (going the other way around the ring from C1, methyl is at position 6). Step 4 (Alphabetical ordering of substituents in the name): Substituents are listed alphabetically: bromo (b) before methyl (m). Step 5 (Compile the name): 2-bromo-6-methyl-cyclohexanecarbaldehyde. Therefore, the correct answer is 2-bromo-6-methyl-cyclohexanecarbaldehyde.