Gold-Catalyzed Atroposelective Synthesis of 1,1'-Binaphthalene-2,3'-diols.

A highly atroposelective (up to 97 % ee) Au-catalyzed synthesis of 1,1'-binaphthalene-2,3'-diols is reported starting from a range of substituted benzyl alkynones. Essential for the achievement of high enantioselectivity during the key assembly of the naphto-3-ol unit is the use of TADDOL-derived α-cationic phosphonites as ancillary ligands. Preliminary results demonstrate that the transformation of the obtained binaphthyls into axially chiral monodentate phosphines is possible without degradation of enantiopurity.