Stereospecific construction of the hydroxytriepoxide system present in triptolide 1 and tripdiolide 2 has been explored starting from levopimaric acid 3. 8α:14α:14α,12α:13α-Diepoxide 9 derived from 3 was converted to the epoxy dienone 16 by four steps process. The 9,11-epoxide group was introduced stereospecifically by oxidation with m-chloroperbenzoic acid to produce diepoxide 20. Epoxidation of the