A malonic ester synthesis of a carboxylic acid proceeds by alkylation of the enolate of the malonic ester followed by ester hydrolysis and decarboxylation of the β-dicarboxylic acid. Which of the following carboxylic acids is difficult to prepare by this method?

A malonic ester synthesis of a carboxylic acid proceeds by alkylation

1.	A malonic ester synthesis of a carboxylic acid proceeds by alkylation of the enolate of the malonic ester followed by ester hydrolysis and decarboxylation of the β-dicarboxylic acid. Which of the following carboxylic acids is difficult to prepare by this method?
A.	PhCH2CH2CO2H
B.	(CH3)2CHO2H
C.	PhCH2CO2H
D.	d)
Answer» D.