See image — Hydrocarbons Chemistry Question

💡 Solution & Explanation

Concept: Peracids (peroxyacids) such as mCPBA or CH3CO3H (peracetic acid) react with alkenes via electrophilic epoxidation. The peracid donates an oxygen to the pi bond in a concerted, syn-addition mechanism, forming an epoxide (oxirane) without ring opening. Step 1 - Identify the reagent: CH3CO3H is peracetic acid, a peroxyacid. Peroxyacids are classic epoxidation reagents for alkenes. Step 2 - Identify the substrate: 1-methylcyclopentene contains a trisubstituted double bond between C1 (bearing the methyl group) and C2 of the cyclopentane ring. Step 3 - Reaction mechanism: The peracid transfers its terminal oxygen to the double bond in a concerted butterfly transition state. This gives direct epoxidation - the two carbons of the double bond become the epoxide carbons with oxygen bridging them. No carbocation intermediate is formed, and no water is involved, so no diol is formed directly. Step 4 - Product: The product is 1-methyl-1,2-epoxycyclopentane, i.e., a cyclopentane ring with an epoxide (oxygen bridge) across C1-C2 and a methyl group at C1. This corresponds to option (c), which shows a cyclopentane ring with a CH3 group at C1 and an epoxide oxygen bridging C1 and C2. Step 5 - Why other options fail: - Option (a): Shows a trans-1-methyl-2-cyclopentanol, which would result from acid-catalyzed ring opening of the epoxide with water, not direct peracid treatment. - Option (b): Shows a product where OH and CH3 appear on the same carbon, inconsistent with epoxidation of 1-methylcyclopentene. - Option (d): Shows a cis-1-methyl-2-cyclopentanol, again a ring-opened product, not the direct epoxidation product. The direct product of peracid epoxidation is the epoxide itself, not the opened diol or alcohol. Therefore, the correct answer is C.