摘要:
The stereochemistry of the formation of tetrahydropyran ring of ent-manoyl oxides from ent-8α-hydroxylabda-13(16), 14-dienes has been studied in one and two-step oxymercuration-demercuration (OM-DM) processes as well as by a new titanium tetrachloride catalyzed cyclization which allows the preparation of this tetrahydropyran moiety of C-13 epimer manoyl oxides in high yield.