An Organophotocatalytic Borylative Minisci Reaction

Key words

Minisci reaction - photocatalysis - azines - pyridines - quinolines - amine–borane adduct

Significance

Leonori and co-workers present an organophotocatalytic borylative Minisci reaction. Strongly acidic and oxidizing conditions ensure the generation of highly nucleophilic boryl radicals in situ, yielding C2-borylated nitrogen heterocycles with moderate regioselectivities and good to excellent yields. Additionally, the authors demonstrate that amine–borylated azines readily engage in conventional organoboron chemistry.

Comment

Polarity-reversal catalysis harnesses the electrophilic or nucleophilic character of radicals to render hydrogen atom-transfer reactions that would otherwise be polarity mismatched kinetically feasible. Because of the nucleophilic character of the respective radicals, amine–boranes themselves have previously been investigated as polarity-reversal catalysts (see Review below). The beauty of this work lies in the translation of this concept into one of the most sought-after transformations for the direct functionalization of N-heterocycles.

Review

B. P. Roberts Chem. Soc. Rev. 1999, 28, 25–35.

Publication History

Article published online:
20 July 2021