Patent ID: 7358378

Claim:
A process for the preparation of paclitaxel, the process comprising: (a) protecting the C(7) and the C(10) hydroxy groups of 10-deacetylbaccatin III (10-DAB) by treating 10-DAB with a bridging silicon-based protecting group to form 10-DAB derivative (12); (b) derivatizing 10-DAB derivative (12) to form 10-DAB derivative (17), the derivatization comprising: (i) treating 10-DAB derivative (12) with a β-lactam side chain precursor to form 10-DAB derivative (13), selectively deprotecting the C(10) hydroxy group of 10-DAB derivative (13) with an alcohol in the presence of a base to form 10-DAB derivative (14), and acetylating the C(10) hydroxy group of 10-DAB derivative (14) to form 10-DAB derivative (17), or (ii) selectively deprotecting the C(10) hydroxy group of 10-DAB derivative (12) with an alcohol in the presence of a base to form 10-DAB derivative (15), acetylating the C(10) hydroxy group of 10-DAB derivative (15) to form 10-DAB derivative (16), and treating 10-DAB derivative (16) with a β-lactam side chain precursor to form 10-DAB derivative (17), and (c) deprotecting 10-DAB derivative (17) to form paclitaxel; wherein 10-DAB derivative (12), 10-DAB derivative (13), 10-DAB derivative (14), 10-DAB derivative (15), 10-DAB derivative (16), and 10-DAB derivative (17), correspond to Formulae (12), (13), (14), (15), (16), and (17), respectively: the bridging silicon-based protecting group corresponds to Formula (2): the β-lactam side chain precursor corresponds to Formula (3B): G 1 , G 2 , G 3 , and G 4 are hydrocarbyl, substituted hydrocarbyl, alkoxy, or heterocyclo; L 1 and L 2 are amine, bromo, chloro, iodo, or sulfonate leaving groups; R 10A is hydrocarbyl; X 6 is a hydroxy protecting group; Z is hydrocarbyl, substituted hydrocarbyl, heterocyclo, —[O—Si(Z 10 )(Z 11 )—] n O—, or —O—; each Z 10 and Z 11 is independently hydrocarbyl; and n is 1 or 2.