Abstract
The 4-nitrophenylsulfonyl, the benzothiazolsulfonyl and the anthracenesulfonyl protecting groups were evaluated in the protection of the phenylisoserine side chain, as part of a semisynthesis of paclitaxel. The mechanism for the cleavage of the anthracenesulfonyl group using thiols was also examined, and found to proceed by an addition elimination pathway, which is in contrast to the reported reductive mechanism. The use of the siamyldimethylsilyl group for protection of baccatin III is discussed and compared with the triethylsilyl group.
Keywords: 4-nitrophenylsulfonamide, benzothiazolsulfonamide and the anthracenesulfonamide, taxol, paclitaxel