Synthesis of hexahydroisobenzofuran-1(3 H )-ones via pyridine-boryl radical-catalyzed intramolecular cascade cyclization of alkene-tethered cyclobutyl ketones

The first pyridine-boryl radical-catalyzed intramolecular formal [4 + 2] cycloaddition of alkene-tethered cyclobutyl ketones has been successfully realized.