HAT Catalysts to Facilitate Acid Mediated Cleavage of Biaryl C–C Bonds in Binaphthols

A method to cleave the C–C biaryl bond of binaphthyl derivatives under reductive conditions is described. Triflic acid employed together with a catalytic HAT reagent, 2-ethyl-9,10-dihydroxyanthracene, that is regenerated using H2 with catalytic Pd/C yielded monomeric products in improved yields. A range of substrates is disclosed, and kinetic analyses provide insight into the mechanism of aryl–aryl activation.