Aminolysis of 2,2-difluoro-4-alkoxy-1,3,2-dioxaborinanes: route to β-keto amides and β-enamino carboxamides

4-Alkoxy substituted 1,3,2-dioxaborinanes 1, readily available from β-keto esters, undergo substitution reactions under mild reaction conditions with primary and secondary amines, deriving the 4-alkylamino analogue 2. Reactions of 1 with substituted phenylhydrazines gave the corresponding hydrazones, or pyrazolones, and 5-alkoxy-1H-pyrazoles as a mixture of products.

A wide variety of 2,2-difluoro-4-alkoxy-1,3,2-dioxaborinanes are converted to the β-keto amides and β-enamino carboxamides via 4-alkylamino-1,3,2-dioxaborinanes using alkylamines.