Natural Taxanes: Developments Since 1828

Paclitaxel is found to be a natural taxane with the most potential. After two decades of effort, at least six groups have achieved the total synthesis of paclitaxel. A diverse strategy and excellent approaches for the synthesis of the taxane framework and for paclitaxel itself were evolved. The construction of the taxane framework with the oxetane ring and the homochiral ester side-chain at C-13 become challenges for synthetic chemists. The in vivo productions of paclitaxel in plant tissue and cell culture have not provided economically feasible solutions to the paclitaxel supply problem. Biotransformation of taxanes, and cell or tissue culture provide breakthroughs continuously for improvement of the paclitaxel production by biological methods. Bioactivity studies of natural taxanes were carried out mostly by Kobayashi group and three comprehensive reviews have been published on these works.