An in-depth DFT insight into the mechanism of NHC-catalyzed generation of p-quinodimethanes: Investigation the role of NHC and different substituents on ε-functionalization

Abstract

Recently, Ye and his co-worker reported a fascinating work that proposed a procedure for generation of p-quinodimethane (p-DQM) via N-heterocyclic carbene (NHC) catalysis for use in the organic synthesis. The remarkable point of this method is related to its capability for ε-functionalization. In this work, the detailed mechanism of NHC-catalyzed production of p-DQM and its ε-functionalization with different trifluoromethyl ketone (TFMK) derivatives were investigated using density functional theory (DFT). Indeed, the role of different substituents on the NHC part of p-QDM on the chemical reactivity and optical properties of this compound was examined. The optical properties and charge transfer indexes were evaluated using TD-DFT method. The results indicated that the chemical reactivity and optical properties of p-QDM compounds can be rationally controlled by the variation of different substituents on the NHC part of them. This computational study paves the way for rational applications of NHC-catalyzed p-QDM in organic synthesis.