Method of preparing taxane derivatives of general formula (I) by esterification of protected baccatine III or 10-deacetyl-baccatine III by means of an acid of general formula (VII), deprotection of the side chain and elimination of the hydroxy function protection groupings. In general formulae (I) and (VII): Ar stands for aryl, R is hydrogen or acetyl, R.sub.1 is benzoyl or R.sub.2 --O--CO-- in which R.sub.2 is alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, bicycloalkyl, phenyl or heterocyclyl, and R.sub.3 is hydrogen, alkoxy, optionally substituted aryl. ##STR1##