A highly efficient protocol for the large-scale oxidative cyclization of 1,5-dienes
is described. This convenient ruthenium(VIII)-catalyzed (0.2 mol%) cyclization reaction
allows the preparation of cis-2,5-disubstituted tetrahydrofurans in high yields (up to 92%) and excellent diastereomeric
ratio (>95:5 dr). This simple and reliable method is insensitive to moisture and air
and can, therefore, be carried out in an open reaction vessel.
ruthenium - oxidation - cyclization - heterocycle - diastereoselectivity