Identify the major product formed in the following reaction.

Step-by-step solution

The given reactant is a bis-epoxide with two cyclopentane rings connected by a single bond. Let's number the carbons of the epoxide rings as C1, C2 and C1', C2', with the rings connected at C3 and C3'. The Grignard reagent, MeMgCl , provides a methyl nucleophile ( Me ⁻ ). Since only 1 equivalent is used, it will attack only one of the epoxide rings. Nucleophilic attack on an epoxide occurs at the less sterically hindered carbon. C1 and C1' are less hindered than C2 and C2' (which are adjacent to the C3-C3' connecti