Acetic Acid → Ethyl 2-cyano-4,4-dimethylpent-2-enoate

A mixture of pivaldehyde (5.00 g, 58 mmol), ethylcyanoacetate (6.60g, 58.3 mmol), acetic acid (3.50 g, 58.3 mmol) and pyridine (4.60 g, 58.2 mmol) was heated at reflux for 1 h. A second portion of pivaldehyde (5.00 g, 58 mmol) was added. The refluxing of the mixture was continued for 18h. After cooling, the mixture was poured into 1N aqueous HCl (50 mL). The resulting mixture was extracted with EtOAc (3×50 mL). The combined organic layers, were washed with 1N aqueous HCl, dried (MgSO4) and concentrated to give a colorless oil. The oil was purified by flash chromatography on SiO2 using hexane-EtOAc (9:1) as the eluant to give 2-cyano-4,4-dimethyl-2-pentenoic acid ethyl ester as a colorless oil (7.69 g, 73 % yield).