oxygen in 5.8. Acetonide Protection: 2,2-dimethoxypropane and camphorsulfonic acid, and dichloromethane Deprotection: Hydrochloric acid, methanol, water, and ethyl ether Protection of the vicinal diol 2.4 allowed the remaining hydroxyl group in alcohol 2.5 to be selectively oxidized to give aldehyde 2.6. The acetonide was removed much later in the synthesis in preparation for the closure of ring D. Bn (benzyl) Protection: Potassium hydride, tetra-n-butylammonium iodide, and benzyl bromide. Deprotection: Hydrogen, Pd(OH)2/C Secondary alcohol 2.2 was protected as the benzyl ether so that the reduction of lactone 2.3 could occur. Protection was removed much later in the synthesis to form alcohol 5.7, which was reprotected as the triethylsilyl ether. Carbonate ester Protection: Potassium hydride, phosgene Deprotection: Phenyllithium opens the carbonate ester ring to give alcohol 6.5. Protection adds rigidity in ring structure for pinacol coupling reaction forming diol 4.9, and also prevents unwanted oxidation in the formation of dialdehyde 4.8. Protection: Tert-butyldiphenylsilyl chloride, imidazole, and dimethylformamide. Deprotection: Tetra-n-butylammonium fluoride Primary alcohol 2.1 was protected in preparation for lactone reduction in 2.3. The protecting group was removed to give diol 4.7 in preparation for the pinacol coupling reaction. TBS (tert-butyldimethylsilyl) [1] Protection: Tert-butyldimethylsilyl triflate, lutidine, 4-(dimethylamino)pyridine, and dichloromethane. Deprotection: Camphorsulfonic acid, dichloromethane, and methanol. The secondary hydroxyl group in 1.8 was briefly protected during the protection of a tertiary hydroxyl group in the same compound. TBS (tert-butyldimethylsilyl) [2] Protection: Tert-butyldimethylsilyl triflate, lutidine, 4-(dimethylamino)pyridine, and dichloromethane. Deprotection: Camphorsulfonic acid Protection of the tertiary hydroxyl group in 1.8 was necessary to allow selective protection of other hydroxyl groups on the C ring. TBS (tert-butyldimethylsilyl) [3] Protection: Dichloromethane, imidazole, and tert-butyldimethylsilyl chloride. Deprotection: Tetra-n-butylammonium fluoride Protection of hydroxyl group in 3.4 allowed the ketone to undergo a Shapiro reaction to form the viyllithium compound 3.7. TES (triethylsilyl) [1] Protection: Triethylsilyl chloride and pyridine. Deprotection: Hydrolysis using hydrofluoric acid, pyridine and tetrahydrofuran. Protection of the secondary hydroxyl group in 5.7 was necessary for the final addition of the tail to alcohol 7.2. TES (triethylsilyl) [2] Protection: See Ojima lactam. Deprotection: Hydrolysis using hydrofluoric acid and pyridine Protected secondary alcohol in Ojima lactam 7.1 during reaction with alcohol 7.2 in the tail addition. See also Paclitaxel total synthesis Danishefsky Taxol total synthesis Holton Taxol total synthesis Kuwajima Taxol total synthesis Mukaiyama Taxol total synthesis Wender Taxol total synthesis External links Nicolaou Taxol Synthesis @ SynArchive.com Taxol in dynamic 3D References Total synthesis Scripps Research Taxanes