Final answer:
Isoborneol is the major product in the reduction of camphor with sodium borohydride due to the more favorable steric and electronic factors during the nucleophilic addition reaction, where the hydride mainly attacks the least hindered side of the carbonyl group in camphor.
Step-by-step explanation:
In the reduction of camphor with sodium borohydride (NaBH4), isoborneol is formed as the major product due to the stereochemical outcome of the reaction. Sodium borohydride acts as a hydride donor in the nucleophilic addition reaction, where the hydride ion (H-) attacks the electrophilic carbon of the C=O group in the camphor molecule. In this context, the carbonyl group of camphor is reduced to a secondary alcohol group, leading to the formation of isoborneol.
Camphor, being a cyclic ketone, presents with steric hindrance around the carbonyl carbon, which will influence the approach of the hydride donor. During the reduction, the least hindered side of the camphor molecule will be the favored site for a hydride attack. Furthermore, the transition state leading to the isoborneol formation is more stable due to steric and electronic factors, resulting in isoborneol being the major product of the reduction.