Enantioselective “Clip-Cycle” Synthesis of Di-, Tri- and Spiro- Substituted Tetrahydropyrans
ω-Unsaturated alcohols were “clipped” via alkene metathesis to a thioester activating group, which was followed by a chiral phosphoric acid catalyzed intramolecular oxa-Michael cyclization to yield tetrahydropyrans and spiro-tetrahydropyrans with...