a method is provided for the semi - synthesis of taxane intermediates useful in the preparation of paclitaxel and docetaxel from 9 - dihydro - 13 - acetylbaccatin iii . the preparation of a suitably protected baccatin iii backbone from 9 - dihydro - 13 - acetylbaccatin iii , and the insertion of the phenylisoserine side chain onto the protected baccatin iii from 9 - dihydro - 13 - acetylbaccatin iii to form the taxane derivatives , paclitaxel and docetaxel is disclosed .