Theoretical study on the isomerization of propargyl derivative to conjugated diene under Au(I)-catalyzed reaction: A DFT study

Abstract

Pure and hybrid quantum mechanical calculations were performed to study the pathway of the isomerization of propargyl derivative to conjugated diene under the catalysis of Au(I) complex derived from the biphenyl-2-ylphosphine with a basic amino group on the pendant phenyl ring. It was previously proposed that a push–pull driving force operates orthogonally during the progress of the reaction. Our study reveals that this push–pull force is syn-periplanar rather than orthogonal. Steric pressure by the phosphine ligand, together with the push–pull interaction favors the transformation of η2 to η1 mode of Au complex. These effects are responsible for the increasing acidity of the transferring proton. The bent structure of the product suffers from the reduced steric pressure, thus favors the formation of the conjugated diene.