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.