Base-free two-step synthesis of 1,3-diketones and β-ketoesters from α-diazocarbonyl compounds, trialkylboranes, and aromatic aldehydes.

We describe a convergent, base-free two-step synthesis of 1,3-diketones and β-ketoesters from α-diazocarbonyl compounds, trialkylboranes, and aromatic aldehydes in a three-component process. The synthetic potential of this protocol was underscored by the synthesis of several symmetrical 1,3,5-triaryl-4-alkyl and 1,3,4,5-tetraryl substituted pyrazoles in a three-step sequence.