Regioselective lactonization of unsymmetrical 1,4-diols: an efficient access to lactone lignans

A Cp*Ru-based bifunctional catalyst system (Cp* = eta(5)-C(5)(CH(3))(5)) with a suitably-designed PN ligand (PN = chelating tertiary phosphine-protic amine ligand) has been developed for a regioselective lactonization of unsymmetrically substituted 1,4-diols, which may provide an expeditious access to a variety of lactone lignans.