Three-component three-bond forming cascade via palladium photoredox catalysis

Chem Sci. 2020 Dec 7;12(5):1810-1817. doi: 10.1039/d0sc05551d.

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.