Mechanism of Side Reactions in Alkane C-H Bond Functionalization by Diazo Compounds Catalyzed by Ag and Cu Homoscorpionate Complexes—A DFT Study

Abstract

DFT computational methods were applied to the mechanistic study of the formation of fumarate and maleate derivatives in a solution containing alkane, TpBr3M [M=Cu, Ag; TpBr3=hydrotris(3,4,5-tribromopyrazolyl)borate] and methyl diazoacetate. These solutions are the experimentally reported conditions for carbene insertion into alkane C-H bonds, a procedure that usually competes with a nondesired reaction, producing fumarate and/or maleate derivatives. Several mechanisms are analyzed. The preferred mechanism proceeds through a direct reaction between a metallocarbene complex intermediate and a diazo molecule. The computational results explain all of the available experimental evidence and provide important information on the behavior of these systems.