Total Synthesis of (+)-Epoxydictymene. Application of Alkoxy-Directed Cyclization to Diterpenoid Construction

摘要

An enantioselective synthesis of (+)-epoxydictymene (1) is reported. Condensation of the enantiopure aldehydo ester 5 with (S)-3-isopropylcyclopentenyllithium proceeds selectively to afford 13. Once this lactions was methylenated with the Tebbe reagent, the newly formed allyl vinyl ether was induced into Claisen rearrangement under catalysis with triisobutylaluminum.