Photocatalyzed Decarboxylative Dual Functional Group Transposition Using Bifunctional Radical Precursors

The remodeling of molecular frameworks provides entry to increased chemical value and complexity from simple starting materials, yet often relies on (hetero)cyclic scaffolds to template the reaction. Herein, we describe a photocatalyzed thermodynamic approach to dual functional group transposition, which relies on radical sorting across linear alkyl frameworks, promoted by visible-light irradiation and decarboxylation. Suitably primed β-thioether or β-boryl carboxylic acids, initially activated as oxime esters, then irradiated in the presence of an energy transfer photocatalyst, undergo radical S,N- or B,N-reconfiguration to generate to 1,2-iminosulfides or 1,2-iminoboronic ester products. Divergent yet related mechanisms for these photocatalyzed transposition processes were investigated using a combination of photophysical, structural, and computational experiments. A suite of 1,2-iminofunctionalized compounds were accessible using this methodology amenable to further synthetic elaboration.