STUDY ON THE SYNTHESIS OF TETRACYCLIC DITERPENOID 7 Preparation of the Key Intermediate 5 for the Synthesis of Grandiflorenic Acid and its Analogues

摘要

The key intermediate 5 for synthesis of the contragestationallyactive diterpenoid grandiflorenic acid（1）and its analogues 2 and 3 wasprepared and an acetyl transposition reaction occurred in the SeO₂ oxida-tion of 8.