Explain why the following carboxylic acids cannot be prepared by a malonic ester synthesis. Part A A line-angle formula shows a ring with six vertices and alternating single and double bonds. A CH2COH group, with an O atom double-bonded to the second (from left to right) carbon atom, is attached to one of the ring vertices. A line-angle formula shows a ring with six vertices and alternating single and double bonds. A CH2COH group, with an O atom double-bonded to the second (from left to right) carbon atom, is attached to one of the ring vertices. An SN2 reaction cannot be done on benzyl bromide. An SN2 reaction cannot be done on bromobenzene. An SN2 reaction cannot be done on dibromobenzene. The bromide required for the synthesis is unstable.