Synthesis of Previously Inaccessible Borylated Heterocycle Motifs Using Novel Boron-Containing Amphoteric Molecules.

The photoredox-organocatalyzed α-alkylation of the α-MIDA boryl aldehyde with a range of α-bromoketones resulted in the first examples of boron-containing 1,4-dicarbonyl compounds. These novel trifunctional amphoteric molecules, which bear an additional, strategically placed electrophilic site compared to the starting amphoteric α-boryl aldehyde, were subjected to double-condensation reactions in the presence of various nucleophiles. As a result, a variety of synthetically challenging 3-borylated pyrroles and furans and 4-borylated pyridazines were generated. The borylated regioisomers accessible with this condensation-based strategy are distinctly different from those arising from the well-known lithiation and C-H activation processes.