Direct, stereoselective synthesis of the protected paclitaxel (taxol) side chain and high-yield transformation to paclitaxel
Abstract
A short, efficient approach to the p-methoxybenzylidene-protected paclitaxel (Taxol) side chain through benzaldehyde benzoylimine-chiral enolate condensation, followed by DDQ-mediated oxazolidine formation and hydrolysis is described; the C-7-triethylsilyl derivative of baccatin III undergoes esterification with this side chain in the presence of DCC and DMAP to provide after acid hydrolysis paclitaxel in excellent overall yield.