Maurizio Fagnoni

We describe herein easily oxidizable 2-substituted-1,3-imidazolidines for the photocatalyzed generation of (substituted) alkyl radicals for the forging of C(sp 3 )–C(sp 3 ) bonds under metal-free conditions.

A visible light‐mediated strategy for the preparation of aromatic stannanes from aryl halides (mostly aryl bromides) is presented herein. The reaction proceeds under metal‐ and additive‐free conditions and exhibits a broad substrate scope. The products obtained have been employed in the C−C bond formation via Stille cross‐coupling reactions. Mechanistic investigation evidenced the key role of both aryl radical and trimethylstannyl radical in Ar−Sn bond formation.

Direct excitation of aromatic compounds grants access to high‐energy intermediates that can be utilised in organic synthesis. Understanding and predicting the substituent effects at the excited state for aromatic molecules remains challenging for the synthetic photochemist. In this work, we present an experimental and computational investigation of the excited state of the isomeric chloroanilines, which promptly react by losing the chloride when the amino group is in para position, but are non‐reactive and non‐emissive in the meta and ortho isomers. XMS‐CASPT2//CASSCF computations explain this apparent contradiction of the meta‐ortho selectivity rule of Zimmerman, which originates from the substituent effects lowering to a different extent the barrier to populate the prefulvenic conical intersection that deactivates non‐radiatively the singlet excited state of the chloroanilines.