See image — Hydrocarbons Chemistry Question

💡 Solution & Explanation

Concept: Peracid (CF3CO3H, trifluoroperacetic acid) epoxidation of alkenes is a stereospecific syn addition, and the starting material is a single enantiomer of vinylcyclopropane (cyclopropyl vinyl compound). Step 1 – Identify the starting material and reagent: The starting material is (vinylcyclopropane derivative) – specifically a cyclopropane ring bearing a -CH=CH2 group. Only one enantiomer is used as starting material. CF3CO3H is a peracid that epoxidizes the double bond. Step 2 – Identify products A and B: Product A (two fused triangles) appears to be a bicyclic compound – likely formed by intramolecular reaction or rearrangement. The Meinwald rearrangement of a vinyl epoxide (or homoconjugated epoxide) can give ring-expanded or rearranged products. Product B (triangle with epoxide) is the direct epoxidation product – a cyclopropane ring bearing an epoxide (spiro or fused epoxide on the vinyl group). Step 3 – Stereochemistry analysis: Since only one enantiomer of the starting material is taken, the peracid epoxidation is a syn addition that can occur from two faces of the double bond. The double bond in vinylcyclopropane is prochiral; epoxidation from the top face gives one diastereomer and from the bottom face gives another diastereomer (because the cyclopropane ring already has a stereocenter). Thus the two products of epoxidation are diastereomers (not enantiomers), since there is already a chiral center in the molecule from the single enantiomer starting material. Step 4 – Nature of A and B as a pair: A and B are formed from the same chiral starting material by reactions that generate different relative configurations. A and B are diastereomers of each other (they have different connectivity or different relative stereochemistry). Each of A and B individually is optically active (since starting from a single enantiomer, each product retains chirality and is not racemic). Step 5 – Evaluate each option: (a) A and B are mixture of diastereomers – This is correct. A and B are diastereomers of each other (different compounds with multiple stereocenters having different relative configurations). (b) A and B are mixture of enantiomers – Incorrect; enantiomers would require mirror-image relationship and same connectivity, which is not the case here since A and B are structurally distinct products (one is a bicycle, one is an epoxide). (c) A and B are optically active – While individually each may be optically active, A and B together constitute a mixture of diastereomers, making option (a) the more precise and complete correct statement. Option (c) is less specific and not the best answer. (d) B is racemic mixture – Incorrect; since we start from a single enantiomer and syn addition gives a specific face selectivity product (or mixture of diastereomers, not enantiomers), B need not be racemic. Therefore, the correct answer is A.