Theoretical Study of Nickel-Catalyzed Proximal C-C Cleavage in Benzocyclobutenones with Insertion of 1,3-Diene: Origin of Selectivity and Role of Ligand.

Martin and co-workers recently developed a strategy for Ni(0)-complex-catalyzed [4 + 4] annulation of primary benzocyclobutenones (BCBs) and 1,3-dienes. A density functional theory study was performed to clarify the catalytic mechanism. The results provide insights into the origins of the chemo-, regio-, and diastereoselectivity. The calculation results explain why only P(C6H5CF3)3, among several candidates, performed well and why the [4 + 4] annulation of BCB with a 1,3-diene was achieved with a Ni(0) but not with a Rh(I) catalyst.