Consider the molecule 1-methylcyclohexene undergoing free-radical bromination with one equivalent of — Haloalkanes and Haloarenes Chemistry Question

💡 Solution & Explanation

Allylic hydrogens are located on $sp^3$ hybridized carbons directly attached to the $sp^2$ carbons of the $C=C$ double bond. In 1-methylcyclohexene, the double bond spans C1 and C2. The C1 carbon is bonded to a methyl group (an allylic position). The C2 carbon is bonded to C3 (a methylene $CH_2$ group, an allylic position). The C1 carbon is also bonded to C6 (a methylene $CH_2$ group, an allylic position). Due to the asymmetry of the molecule (the methyl group is only on C1), the $CH_2$ protons at C3 are chemically distinct from the $CH_2$ protons at C6. Therefore, there are exactly 3 distinct allylic hydrogen environments: the $CH_3$ group, the C3 $CH_2$ group, and the C6 $CH_2$ group.