2,2’-Dihalo-1,1’-binaphthyl compounds can introduce coordinating groups and other complex functional systems into the binaphthyl skeleton; however, their structural diversity renders preparation challenging. In this study, a streamlined approach is developed to prepare dihalobinaphthyl compounds that uses designed, easily obtained α-hydroxyl haloalkynes as the starting materials, which combine activity of haloalkynes and traceless directional hydroxyl groups. This process involves a palladium-catalysed 1,2-halo shift, electrophilic carbocyclisation, dehalogenative coupling with another α-hydroxyl haloalkyne, and halogenated electrophilic cyclisation. Density functional theory calculations shows the occurrence of 1,2-halo shift is primarily governed by the coordination of the aromatic ring in the palladium catalyst. The target 2,2’-dihalo-1,1’-binaphthyl compounds can be prepared on the gram scale, and afford a series of ligands, catalysts, and high-value binaphthyl-based materials. This method will significantly expand the synthetic toolbox for dihalobinaphthyl compounds and create possible opportunities for preparing functionally diverse binaphthalene-based architectures with tailored properties. Authors present syntheses of 2,2’-dihalo-1,1’-binaphthyl compounds using easily-obtained α-hydroxyl haloalkynes as the starting materials. The resulting compounds can be prepared on the gram scale, and afford a series of ligands, catalysts, and high-value binaphthyl-based materials.
Ji et al. (Wed,) studied this question.