title: Stereoselective convergent synthesis of a trans-fused polycyclic ether ring system including a 4-hydroxy-5-methyl-tetrahydropyran ring.
abstract: [reaction: see text] Stereoselective convergent synthesis of a trans-fused 6-6-6-6-membered tetracyclic ether ring system including 4alpha- or 4beta-hydroxy-5-methyl-tetrahydropyran was achieved. The key reactions involve the acetylide-aldehyde coupling of two tetrahydropyrans, intramolecular hetero-Michael cyclization of enone, stereoselective reduction of enone, hydroboration, intramolecular acetalization, and stereoselective reduction of the acetal with Et(3)SiH-TMSOTf.
authors.affiliation: Graduate School of Science and Engineering, Saitama University, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Suzuki
authors.forename: Tadashi
authors.initials: T
authors.lastname: Nakata