See image — Alcohols Phenols and Ethers Chemistry Question

💡 Solution & Explanation

Step 1 - Epoxidation with RCO3H: Cyclohex-1-ene reacts with a peracid (RCO3H) to form cyclohexene oxide (1,2-epoxycyclohexane). The oxygen is delivered in a syn (cis) fashion to the double bond, giving a cis-epoxide. Step 2 - Grignard opening with CH3MgBr: The Grignard reagent (CH3MgBr) opens the epoxide via an SN2 mechanism. SN2 attack proceeds with inversion at the carbon being attacked. Since the epoxide is symmetrical (cyclohexene oxide), the methyl nucleophile attacks one carbon from the back face, resulting in inversion at that carbon. The oxygen and the incoming methyl group end up trans to each other (anti addition overall). Step 3 - Protonation with H+/H2O: The alkoxide intermediate is protonated to give the alcohol. Overall stereochemical outcome: The epoxide oxygen and the CH3 group are introduced with net anti addition across the original double bond. This gives a trans relationship between the OH and CH3 groups on the cyclohexane ring, i.e., trans-2-methylcyclohexan-1-ol. The product shown in option (b) depicts OH on a dashed bond and CH3 on a wedge bond at adjacent carbons, representing a trans (diaxial/diequatorial) relationship - the trans isomer. Why other options fail: - Option (a) shows a cis relationship (both substituents on the same face), which would result from retention, not inversion - incorrect for SN2 epoxide opening. - Option (c) shows a diol on a cyclohexene ring, which would be the product of OsO4 dihydroxylation, not the given sequence. - Option (d) shows 1-methylcyclohex-2-ene, a simple alkene with no oxygen functionality, which does not account for the epoxide opening. Therefore, the correct answer is B.