Conjugate-like addition of soft nucleophiles to 8-alkenylBODIPYs

Meso-phenylethenylBODIPY 8 was prepared using the Liebeskind-Srogl cross-coupling reaction. The reactivity of 8 was evaluated in the addition of soft nucleophiles observing that, in all the cases studied, the addition took place exclusively at the b-alkene position with good chemical yields under mild conditions. While the starting BODIPY 8 was non-emissive, all of the adducts were highly fluorescent in MeOH, except for meso-coumarinBODIPY 11. However, when the fluorescence of 11 was measured in EtOAc, a 41-fold increase was observed. This behaviour was explained in terms of a photoinduced electron-transfer phenomenon.