Cyclohexene oxide (1,2-epoxycyclohexane) is treated with HBr. The product formed is:

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Question

Cyclohexene oxide (1,2-epoxycyclohexane) is treated with HBr. The product formed is:

Accepted Answer

Correct Answer: C — trans-2-BromocyclohexanolStep-by-step Solution:Cyclohexene oxide is an epoxide (three-membered cyclic ether). When treated with HBr (acid conditions):Step 1: H+ from HBr protonates the epoxide oxygen, making it a better leaving group.Step 2: Br- acts as a nucleophile and attacks one of the carbons of the protonated epoxide from the back side (SN2-like mechanism, anti-addition).Step 3: The ring opens to give a product where -Br and -OH are on adjacent carbons in an anti (trans) arrangement.Product: trans-2-Bromocyclohexanol.Why other options are incorrect:Option A (Cyclohexene): Elimination would require a base, not HBr under acidic conditions.Option B (Cyclohexanol): This would require H2O as the nucleophile (acid-catalysed hydrolysis of epoxide), not HBr.Option D (1,2-Dibromocyclohexane): This would result from addition of Br2 to cyclohexene, not from HBr acting on an epoxide.Key Concept: Acid-catalysed ring opening of epoxides follows anti-addition (SN2-like). The nucleophile attacks from the side opposite to the C-O bond being broken. For a symmetric epoxide like cyclohexene oxide, both carbons are equivalent, and the product has the nucleophile and the -OH in trans configuration.

Cyclohexene oxide (1,2-epoxycyclohexane) is treated with HBr. The product formed is:

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Cyclohexene oxide (1,2-epoxycyclohexane) is treated with HBr. The product formed is:

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