Structure elucidation of some ent-clerodane diterpenes from Dodonaea boroniaefolia and Cyanostegia augustifolia

Abstract

Two diterpene alcohols (1) and (2) and a hydroxy acid isolated as the ester (7) have been obtained from D. boroniaefolia. Their structures have been established by correlation with the acid (10) by way of the cyclopropane intermediate (17) and its product of ring opening (22). The diacid (24) from Cyanostegia angustifolia has also been correlated with (22) through the diol (29) and keto acid (31).