Controlling substrate selectivity in cross coupling with light

Substrate-selective reactions typically rely on differences in the ground-state reactivity of substrates or their interactions with supramolecular catalyst scaffolds. Here, we show that a photoinduced cross-coupling reaction provides high substrate selectivity that cannot be achieved under thermal conditions. We report a visible-light-promoted, Ni-catalyzed Suzuki–Miyaura cross-coupling of diiodo-boron-dipyrromethene (BODIPY) chromophores displaying high selectivity for mono-arylation, enabling the efficient sequential synthesis of unsymmetrically substituted BODIPYs. Substrate selectivity is maintained in mixtures containing non-absorbing aryl iodides or halogenated BODIPYs with similar absorption. This work demonstrates the potential of substrate photoexcitation-based reaction mechanisms for the selective functionalization of organic chromophores with desirable excited-state properties.