Question

based on conditions, identify where a nucleophilic attack would occur on the following epoxides. image of two epoxide structures labeled acidic (with positions i, ii) and basic (with positions iii, iv) a. i and iii b. i and iv c. ii and iii d. ii and iv

Explanation:

1. Acidic Conditions (Epoxide Ring-Opening): In acidic conditions, the epoxide oxygen is protonated, making the ring more electrophilic. The nucleophile attacks the more substituted carbon (due to better stabilization of partial positive charge via hyperconjugation/inductive effects). In the "acidic" epoxide, position II is the more substituted carbon (or the carbon with more alkyl groups), so nucleophilic attack occurs at II.
2. Basic Conditions (Epoxide Ring-Opening): In basic conditions, the nucleophile attacks the less substituted carbon (due to steric hindrance; the less substituted carbon is more accessible). In the "basic" epoxide, position III is the less substituted carbon (or the carbon with fewer alkyl groups), so nucleophilic attack occurs at III.

Combining these, the correct sites are II (acidic) and III (basic), matching option C.

Answer:

C. II and III