Dolastatins 24. Synthesis of (-)-dolastatin 10. X-Ray molecular structure of N,N-dimethylvalyl-valyl-dolaisoleuine tert-butyl ester

Total synthesis of the extraordinary antineoplastic constituent, dolastatin 10, from the Indian Ocean mollusc Dolabella auricularia has been summarized. The final synthetic step involved diethyl cyanophosphonate-mediated coupling of Dov-Val-Dil with Dap-Doe. Improved syntheses of these important precursors has led to a very practical synthesis of natural dolastatin 10. Important details of the HPLC and high-field (500 MHz) NMR characterization techniques employed to confirm the purity of dolastatin 10 have been recorded.