Which combination of reagents would you use to synthesize the ester ${\mathrm{CH}}_3\mathrm{COOCH}{3}_{}$ (methyl acetate)?

• A. ${\mathrm{CH}}_3\mathrm{COOH}$ (acetic acid) and ${\mathrm{CH}}_3\mathrm{OH}$ (methanol) in the presence of an acid catalyst
• B. ${\mathrm{CH}}_3\mathrm{OH}$ (methanol) and ${\mathrm{CH}}_3\mathrm{COCH}{3}_{}$ (acetone) in the presence of an acid catalyst
• C. ${\mathrm{CH}}_3\mathrm{CHO}$ (acetaldehyde) and ${\mathrm{CH}}_3\mathrm{OH}$ (methanol) in the presence of a base
• D. ${\mathrm{CH}}_3\mathrm{COOH}$ (acetic acid) and ${\mathrm{CH}}_3\mathrm{NH}$₂ (methylamine) in the presence of a base

Answer: (A)

Verified step by step guidance

1. Identify the target ester: methyl acetate has the structure \(\mathrm{CH_3COOCH_3}\), which means it is formed from acetic acid (\(\mathrm{CH_3COOH}\)) and methanol (\(\mathrm{CH_3OH}\)).
2. Recall the general method for ester synthesis: esters are commonly synthesized by the acid-catalyzed reaction between a carboxylic acid and an alcohol, known as Fischer esterification.
3. Write the general Fischer esterification reaction: \(\mathrm{R-COOH + R'-OH \xrightarrow{H^+} R-COOR' + H_2O}\) where \(\mathrm{R-COOH}\) is the carboxylic acid and \(\mathrm{R'-OH}\) is the alcohol.
4. Match the reagents to the target ester: since methyl acetate has a methyl group on the oxygen side, the alcohol must be methanol (\(\mathrm{CH_3OH}\)), and the acid must be acetic acid (\(\mathrm{CH_3COOH}\)).
5. Confirm the presence of an acid catalyst is necessary to protonate the carbonyl oxygen, increasing electrophilicity and facilitating the nucleophilic attack by the alcohol, thus driving the esterification forward.