Final Answer:
In the context of tertiary electrophiles, the SN1 (substitution nucleophilic unimolecular) pathway is favored over E2 (elimination bimolecular) reactions.
Step-by-step explanation:
Tertiary electrophiles, characterized by a carbon atom bonded to three other carbon atoms, exhibit a high tendency to undergo SN1 reactions due to the stabilization of the carbocation intermediate formed during the process. In SN1 reactions, the leaving group departs first, generating a carbocation, which is then attacked by a nucleophile. The tertiary carbocation formed in this scenario is relatively stable due to the surrounding alkyl groups providing electron density through hyperconjugation. Consequently, SN1 reactions are preferred over E2 reactions.
E2 reactions involve the elimination of a leaving group and a proton from adjacent carbons, leading to the formation of a double bond. However, in the case of tertiary electrophiles, steric hindrance becomes a significant factor. The crowded environment around the tertiary carbon makes it challenging for the nucleophile to access the hydrogen atom for elimination. This steric hindrance impedes the E2 pathway, making SN1 the more favorable route.
In summary, the preference for SN1 over E2 in tertiary electrophiles is attributed to the stabilization of the tertiary carbocation and the steric hindrance hindering the E2 pathway. Understanding these factors is crucial in predicting and rationalizing the outcomes of reactions involving tertiary electrophiles.