Mechanism of Palladium‐Catalyzed Spiroannulation of Naphthols with Alkynes: A Density Functional Theory Study

Abstract

The Cover Feature shows ortho-bromophenylnaphthalenols and acetylene substrates that, just like the fish in the sea, jump through an energy barrier to achieve the spiroannulation product. In their Full Paper, X. Luo et al. performed DFT calculations to investigate the mechanism and enantioselectivity of Pd-catalyzed spiroannulation of ortho-bromophenylnaphthalenols with acetylenes to achieve asymmetric dearomatization. They propose that the catalytic cycle is composed of an oxidative addition of the aryl bromide to Pd(0) to afford an aryl palladium species, followed by acetylene insertion into the Pd–C(aryl) bond, Pd-assisted intramolecular deprotonation of the naphthol moiety and reductive elimination to give the spiroannulation product. They found that both the rate- and enantioselectivity-determining steps are acetylene insertion, and explained that the enantioselectivity is controlled by the steric repulsion between the naphthol moiety and the ligand. More information can be found in the Full Paper by X. Luo et al.