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.
Waldhart, G. W., & Mankad, N. P. (2015). Photochemical Heck benzylation of styrenes catalyzed by Na[FeCp(CO)2]. Journal of Organometallic Chemistry, 793, 171–174. https://doi.org/10.1016/j.jorganchem.2014.12.033