Alditol thiacrowns via a ring-closing metathesis of carbohydrate-derived α,ω-dithioallylethers

We report a newly developed synthesis of a number of alditol thiacrowns using an eco-friendly and versatile two-step strategy: the regioselective thioallyletherification of a polyhydroxylated alditol followed by a ring closing metathesis using the Grubbs second generation catalyst. This approach allows a series of target thiacrown products to be obtained in acceptable to good yields, from the corresponding α,ω-dithioallylether alditol starting materials featuring either the xylo, ribo, threo, erythro, d-manno or d-gluco configurations. The per-O-acetylated d-mannitol dithioallyether 10, easily obtained on a large scale using this approach, was selected for evaluation as both an antibacterial and an antioxidant. Although no antibacterial activity was observed for the bacterial strains investigated, compound 10 is shown to be an antioxidant, and able to quench hydrogen peroxide in a stoichiometric fashion.