Metal-Free Conjugate Addition of Alkenylboronic Acids to Enedicarbonyl Compounds towards the Synthesis of Pyridazine Derivatives

Abstract

The regioselective conjugate addition of alkenylboronic acids to electronically-differentiated 1,4-enedicarbonyl compounds under metal-free conditions, using tartaric acid as promoter of the reaction is reported. The resulting compounds have been used as starting materials in the synthesis of 4-alkenyl-4,5-dihydropyridazin-3(2H)-ones or 4-alkylpyridazin-3(2H)-ones by reaction with hydrazine hydrate and acetic acid.

Key words

boron - cyclization - isomerization - Michael addition - nucleo­philic addition

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