Photochemical Heck benzylation of styrenes catalyzed by Na[FeCp(CO)2]

•The [CpFe(CO)2]– anion was found to catalyze Heck benzylation of styrenes.•Catalyst optimization and substrate scope were explored.•Preliminary mechanistic experiments and discussion are presented.

Iron-catalyzed Heck coupling of benzyl chlorides and styrenes proceeds under photochemical conditions using the well-known anionic complex, [FeCp(CO)2]- (Fp−), as a catalyst. The reaction likely proceeds through the established SN2 mechanism for Fp− alkylation, followed by styrene migratory insertion and β-hydride elimination steps that are enabled by photochemical CO dissociation.

Graphical abstractThe Fp anion acts as a catalyst for Heck benzylation of styrenes upon photochemical activation, allowing for conversion of alkene C–H bonds to C–C bonds without use of a precious metal catalyst.Figure optionsDownload full-size imageDownload as PowerPoint slide