Three-component three-bond forming cascadeviapalladium photoredox catalysis

Abstract

A highly modular radical cascade strategy based upon radical cyclisation/allylic substitution sequence between alkyl/aryl bromides, 1,3-dienes and nucleophiles ranging from sulfinates to amines, phenols and 1,3-dicarbonyls is described (>80 examples). Palladium phosphine complexes - which merge properties of photo- and cross coupling-catalysts - allow to forge three bonds with complete 1,4-selectivity and stereocontrol, delivering highly value added carbocyclic and heterocyclic motifs that can feature -inter alia- vicinal quaternary centers, free protic groups,gem-difluoro motifs and strained rings. Furthermore, a flow chemistry approach was for the first time applied in palladium-photocatalysed endeavors involving radicals.