Q17-77E - Organic Chemistry (Mcmurry)

Question

Ethers can be prepared by reaction of an alkoxide or phenoxide ion with a primary alkyl halide. Anisole, for instance, results from reaction of sodium phenoxide with iodomethane. What kind of reaction is occurring? Show the mechanism.

Step-by-Step Solution

Answer

Step 1: Nucleophile

Nucleophiles are electron rich species which attack electron deficient species. Arrows in a nucleophilic reaction are shown toward electron deficient species.

Step 2: Electrophile

Electrophiles are electron deficient species which are attacked by electron rich species known as nucleophiles.

Step 3: S N 2 reaction

${\mathrm{S}}_{\mathrm{N}}2$ reaction is a nucleophilic substitution reaction in which a bond is broken and another bond is formed synchronously. Here nucleophile attack an electrophilic region. 

Step 4: Reaction occuring

Here ${\mathrm{S}}_{\mathrm{N}}2$ reaction is occurring in which phenoxide ion forms bond with methyl of methyl iodide and simultaneously bond between methyl and iodide is broken. The resulting molecule is methoxybenzene.

                                                          ${\mathrm{S}}_{\mathrm{N}}2$ mechanism