Gold-catalyzed asymmetric allylic substitution of free alcohols: An enantioselective approach to chiral chromans with quaternary stereocenters for the synthesis of Vitamin E and analogues

The enantioselective synthesis of α- and γ-tocopherol (the most biologically active members of vitamin E family) and analogues has been accomplished employing a new enantioselective gold catalyzed intramolecular allylic alkylation reaction followed by an olefin cross-metathesis as key steps. The methodology proved to be applicable to different olefins highlighting its potential for the synthesis of diverse libraries. The enantioselective synthesis of α- and γ-tocopherol (the most biologically active members of vitamin E family) and analogues has been accomplished employing an enantioselective gold-catalyzed intramolecular allylic alkylation reaction followed by an olefin cross-metathesis as key steps (see scheme).