TAXUS-CANADENSIS TAXANES - STRUCTURES AND STEREOCHEMISTRY

The structures and stereochemistry of 14 taxanes isolated from Taxus c anadensis have been rigorously established by high-resolution NMR tech niques and mass spectrometry. Taxus canadensis is the only yew that ac cumulates 9-dihydro-13-acetylbaccatin III (also called 7,9-deacetylbac catin VI) as the most abundant taxane. Five 9-dihydrotaxanes derived f rom the Canadian yew are novel natural products not reported in the ne edles of other species of yew (8-11, 14, Fig. 1).