Identify the major organic products A and B in the following reaction scheme.

Step-by-step solution

The starting material is a cyclic compound containing two functional groups: a ketone and a lactone (cyclic ester). Specifically, it is 3-methyl-tetrahydro-2H-pyran-2,5-dione. 1. Reaction with NaBH ₄ (Product A): Sodium borohydride ( NaBH ₄ ) is a mild reducing agent. It selectively reduces aldehydes and ketones to their corresponding alcohols but is not strong enough to reduce esters or lactones. Therefore, the ketone group at the C5 position is reduced to a secondary alcohol ( -CH(OH)- ), while the lactone ring r