Predict the product for the following reaction and write a mechanism to explain how it is formed.

Verified step by step guidance

1. Identify the type of reaction: The presence of a secondary alkyl halide (Br) and a protic solvent (CH3OH) suggests an SN1 or E1 mechanism.
2. Consider the stability of the carbocation: The secondary carbocation formed after the departure of the bromide ion can be stabilized by resonance with the adjacent double bonds.
3. Determine the mechanism: Given the stability of the carbocation and the protic solvent, an SN1 mechanism is likely, where the carbocation intermediate is formed.
4. Predict the nucleophilic attack: Methanol (CH3OH) will act as a nucleophile and attack the carbocation, forming an ether product.
5. Proton transfer: The final step involves the deprotonation of the oxonium ion by another methanol molecule, resulting in the formation of the ether product.

Key Concepts

Nucleophilic Substitution Reactions

Nucleophilic substitution reactions involve the replacement of a leaving group (like Br) by a nucleophile (like CH3OH). In these reactions, the nucleophile donates a pair of electrons to form a new bond, while the leaving group departs with its electrons. Understanding the mechanism, whether SN1 or SN2, is crucial for predicting the product and the reaction pathway.

SN1 vs. SN2 Mechanisms

The SN1 mechanism is a two-step process where the leaving group departs first, forming a carbocation intermediate, followed by nucleophilic attack. In contrast, the SN2 mechanism is a one-step process where the nucleophile attacks the substrate simultaneously as the leaving group departs. The choice between these mechanisms depends on factors like substrate structure and the strength of the nucleophile.

Carbocation Stability

Carbocation stability is a key factor in determining the pathway of nucleophilic substitution reactions. More stable carbocations (tertiary > secondary > primary) are favored in SN1 reactions, as they can better accommodate the positive charge. Understanding the stability of intermediates helps predict the likelihood of SN1 versus SN2 mechanisms and the resulting products.