The Role of Copper in Homogeneous Catalysis: Single Electron Transfer and Beyond

Identifier:  TDX:3006

Handle: https://hdl.handle.net/20.500.11797/TDX3006

Authors:  Ni, Shaofei

Abstract:
A better mechanistic understanding of Cu-catalyzed organic synthesis is highly desirable, especially in cases involving single electron transfer (SET). In this thesis, we carry out DFT calculations on the mechanism of four different representative Cu-catalyzed or co-catalyzed organic reactions. -The mechanism of a C-C coupling process via Cu-catalyzed borylative ring closing is studied. The role of different factors, such as the nature of the organic reactant R, the leaving group X, and the counter cation C in the base, are elucidated. -We uncovers a new general manifold of the role of single electron transfer process in the enantioselective intermolecular cyanotrifluoromethylation of styrenes using chiral bis(oxazoline)/Cu(I) catalyst. The origin of enatioselectivity is also rationalized from the non-covalent interactions (NCI), the energy decomposition analysis, and the charge decomposition analysis. -An alternative mechanism, different from that proposed from experiment, has been characterized for the iridium-catalyzed aerobic α,β-dehydrogenation of γ,δ-unsaturated amides and acids under the presence of Cu(OAc)2•H2O with O2 as oxidant. The AgBF4 and [Cu(OAc)2•H2O]2 units are shown to play an important role; the silver complex activates the initial Ir(III) catalyst by Cl abstraction and the copper complex cooperates in the C-H activations and facilitates the catalyst recovery by Ir(I) oxidation. -We clarify the mechanism of the oxidative synthesis of 1H-indazole through C-H amidation and N-N bond formation in the presence of a Rh(III)/Cu(II)-cocatalyst system. The key step is the N-N bond reductive elimination from the Cu(III) center. The interactions between the Cu and Rh connected by the acetate ligand and the coordination of the substrate to the Rh(III) center play an important role in the transition state for this step.