Stereoselective Convergent Synthesis of a trans-Fused Polycyclic Ether Ring System Including a 4-Hydroxy-5-methyl-tetrahydropyran Ring

摘要

Stereoselective convergent synthesis of a trans-fused 6-6-6-6-membered tetracyclic ether ring system including 4α- or 4β-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_3SiH-TMSOTf.