Regioselective synthesis of 2-chloro-3-pyridinecarboxylates

2-Chlorocyanoacetate was found to undergo base-catalyzed Michael addition to ,β-unsaturated ketones or aldehydes to afford 5-oxopentenenitrile derivatives. In the presence of anhydrous HCl, these compounds cyclize to yield 2-chloro-3-pyridinecarboxylates. The process is highly regiospecific and useful in the synthesis of 2,3-disubstituted pyridines.