Stereocontrolled synthesis of substituted bicyclic ethers through oxy-Favorskii rearrangement: total synthesis of (±)-communiol E.

The potential of the oxy-Favorskii rearrangement to form branched cis-fused bicyclic ethers was explored. Both tertiary and quaternary centers were constructed in highly stereospecific manners. Methanol and primary amines were effective nucleophiles for the rearrangement. The total synthesis of (±)-communiol E was achieved based on this method.

Organocatalytic enantioselective synthesis of nitrogen-substituted dihydropyran-2-ones, a key synthetic intermediate of 1beta-methylcarbapenems.

Organocatalytic enantioselective cycloadditions providing nitrogen-substituted dihydropyran-2-ones were developed in two catalytic systems. The (3R,4R)-product was a versatile intermediate in the synthesis of 1beta-methylcarbapenem antibiotics.