Theoretical study on the reaction mechanism of Pd(OAc)(2)-catalyzed trifluoroethylation: Role of additive CF3COOH

摘要

The mechanism of Pd(OAc)(2)-catalyzed trifluoroethylation of aromatic systems is explored using the density function theory (DFT) computations. The calculation results indicate that the whole catalytic cycle involves a coordinated process of catalyst Pd(OAc)(2) with acetanilide la, a C-H bond activation and a two-step migration of CF3CH2-group. The interesting role of additive (CF3COOH) is that it can react with substrate 2a (mesityl(trifluoroethyl)iodonium triflate) to form an active species mesityl(trifluoroethyl) iodonium trifluoroacetate 2a'. 2a' can assist the C-H activation to decrease the rate-limiting free energy barrier of the catalytic reaction by changing the rate-limiting step from the transferring process of CF3CH2-group to the C-H bond activation. (C) 2017 Elsevier Ltd. All rights reserved.