A Double Ring‐Closing Metathesis Approach for the Synthesis of β‐C‐Trisaccharides

Good things come in threes: A variety of β-C-trisaccharides have been successfully synthesized by double ring-closing metathesis, which provides the products in excellent overall yield after functionalization of the newly formed double bonds (see scheme). The precursor olefin–enol ethers were prepared by Takai methylenation of the appropriate diesters.