Answer:
tetrahedral aldehyde
Step-by-step explanation:
- The reaction begins with a hydride nucleophile reacting with the ester carbonyl carbon to form the tetrahedral intermediate.
- The carbonyl reforms to produce an aldehyde with the loss of the alkoxide ion.
- The resulting aldehyde undergoes a subsequent reaction with a hydride nucleophile to form another tetrahedral intermediate. The carbonyl is not able to reform, because there are no stable leaving groups.
- Therefore, the tetrahedral intermediate is protonated to produce a primary alcohol.