Theoretical studies of nickel-catalyzed ring-opening hydroacylation of methylenecyclopropanes and benzaldehydes.

Density functional theory (DFT) was used to investigate nickel-catalyzed ring-opening hydroacylation of methylenecyclopropanes and benzaldehydes. The results indicated that the Ni-P(n-Bu)3 complex exhibited much more excellent catalysis than the other two complexes (Ni-PMe3 and Ni-P(t-Bu)3). The hydrogen migration was the rate-determining step, and the β-carbon elimination was the chirality-limiting step. The dominant product was a (S,S)- cis ketone. The phosphine ligand P(n-Bu)3 changed the rate-determining step, and greatly decreased the free energies of the rate-determining step and chirality-limiting step. The use of P(n-Bu)3 generally decreased the free energies of the intermediates and transition states. The possible role of P(n-Bu)3 was the transformation of the electron and geometry structures of those intermediates and transition states. Graphical Abstract DFT results indicated that the Ni-P(n-Bu)3 complex exhibited much more excellent catalysis than the other two complexes (Ni-PMe3 and Ni-P(t-Bu)3). The phosphine ligand P(n-Bu)3 changed the rate-determining step, and greatly decreased the free energies of the rate-determining step and chirality-limiting step.