Constituents of Solidago Species. Part III. The Constitution of Diterpenoids from Solidago juncea Ait.

Abstract

The constitution and stereochemistry of five new diterpenoids from Solidago juncea Ait., junceic acid (3a), the related epoxide (6a), junceanol W(4a), junceanol X (4b), and junceanol Y (5a), have been assigned on the basis of their chemical and spectroscopic properties. Of key importance in these deductions have been the transformations of 4b and 5a into the previously described hydrocarbon 19 and of 3a into 3e. Two known diterpenoids, (−)-hardwickiic acid (2a), which has also been converted into 3e, and ent-16-kauren-19-oic acid (1), are further constituents of S. juncea.