The present invention relates to a stereoselective synthesis of novel β-lactam dimers as useful precursors for the preparation of paclitaxel, docetaxel, and analogues thereof. More particularly, the new β-lactams are prepared from readily available and enantiomerically pure chiral auxiliaries. The β-lactams are then reacted with a suitably protected taxane to produce diastereomerically enriched side chain-bearing taxanes. Finally, the chiral auxiliary is cleaved and protecting groups are removed to provide the desired taxane.