Event
Title: Computational Studies of Functionalization of C-H, C-C Bonds and Olefins
Abstract:
Due to limited mechanistic insights, catalyst design and optimization in transition metal catalysis are often based on chemical intuition. I will discuss two examples in which computations have revealed novel and counterintuitive mechanistic understanding that refined the catalyst design principles: (1) In transition-metal catalyzed C-H and C-C bond functionalization reactions, significant amount of previous research has focused on the mechanism and selectivity of the initial C-H/C-C bond cleavage (metalation) step. Our computational studies have indicated that a number of experimentally observed reactivity and selectivity trends are indeed originated in the subsequent functionalization of the C-H/C-C metalated intermediate, rather than in the metalation step itself. (2) We developed a Ligand-Substrate Interaction Model to reveal the nature of the through-bond and through-space interactions between the metal catalyst and the substrate and to predict the effects of such interactions on reactivity and selectivity. Although the conventional understanding of the non-bonding interaction between ancillary ligand and substrate is mainly steric repulsions, we have demonstrated the stabilizing dispersion interactions between the substrate and bulky bisphosphine ligand promote the Cu-catalyzed hydroamination of unactivated aliphatic olefins.
Representative publications:
Topic #1: C-H and C-C bond functionalization:
Omer, H. M.; Liu, P.*: “Computational Study of Ni-Catalyzed C−H Functionalization: Factors that Control the Competition of Oxidative Addition and Radical Pathways,” J. Am. Chem. Soc., 2017, 139, 9909–9920.
Topic #2: Olefin hydrofunctionalization
Lu, G.; Yang Y.; Liu, R. Y.; Fang, C.; Lambrecht, D. S.*; Buchwald, S. L.*; Liu, P.*: “Ligand-Substrate Dispersion Facilitates the Copper-Catalyzed Hydroamination of Unactivated Olefins,” J. Am. Chem. Soc. in press, DOI: 10.1021/jacs.7b07373.
Inquires please contact Rosa M. Vargas rvargas@sas.upenn.edu