Highly Enantioselective Organocatalytic Addition of Aldehydes to<i>N</i>-(Phenylmethylene)benzamides: Asymmetric Synthesis of the Paclitaxel Side Chain and Its Analogues
Easily side‐tracked: A simple route to the paclitaxel side chain and its analogues is based on the (R)‐proline‐catalyzed addition of aldehydes to N‐(phenylmethylene)benzamides, followed by oxidation of the resulting protected α‐hydroxy‐β‐benzoylaminoaldehydes (92–99 % ee). Esterification of the subsequent phenylisoserine derivatives with baccatin III gives paclitaxel analogues (see scheme).