Mechanistic insight into the [2 + 2 + 2] cycloadditions between 1,6-diyne and benzoquinone catalyzed by rhodium complex: A theoretical study

Abstract

The coupling reaction mechanism of 1,6-diyne with benzoquinone catalyzed by rhodium complex was studied by density functional theory (DFT) calculations. The [2 + 2 + 2] cycloaddition reaction include four main steps: oxidative cyclization, olefin insertion, σ-bond metathesis, and H-transfer, respectively, which would lead to the major product naphthoquinone. The olefin insertion is the chemoselectivity-determining step and the electronic effect could account for the observed chemoselectivity. The effect of different substituents of benzoquinone on the yield was also clarified through our calculations.