Synthesis of the Ziegler Key Intermediate and Related Precursors for the Synthesis of Forskolin and Erigerol in Enantiomerically Pure Form

Abstract
The Ziegler key intermediate 5, previously used in three total synthesis of forskolin (1), and the intermediate 4, potentially useful for the synthesis of erigerol (2), were obtained in optically pure form by the resolution of the allylic alcohol 7a with R-(-)-O-methylmandelic acid.