Propose an efficient synthesis for each of

Step 1 of 4

(a) The first reaction begins with cyclohexyl bromide.

To attach the carbonyl, we first treat the starting material with magnesium which produces a Grignard reagent. The relative electronegativities of carbon and magnesium place a large negative charge on the brominated carbon, which can attack the electrophilic carbon of carbon dioxide to yield a carboxylate intermediate. Quenching with ethyl iodide leads to the desired ethyl ester.