Methods of preparing amino acid-substituted taxanes such as: using selected blocked amino acids are disclosed. After coupling of the blocked amino acid to the taxane, deprotection is carried out with about an equimolar amount of a secondary amine thus substantially avoiding base-catalyzed hydrolysis of amino acid from the taxane. The preferred amino acid-taxanes are useful as intermediates in the production of polymer conjugated therapeutic compositions or as part of pharmaceutically acceptable formulations.