Total synthesis of the complex taxane diterpene canataxpropellane

Synthesis of Taxol's complicated cousin Propellane molecules contain three rings that all share a common edge, thereby collectively resembling a propeller. Canataxpropellane, a yew-derived natural product related to the cancer drug Taxol, is unusual in that it has two different propellane motifs in its backbone. Schneider et al. report a chemical synthesis of this intricate compound in under 30 steps. Key features of the route include a Diels-Alder reaction rendered asymmetric by introduction of a chiral silyl auxiliary, followed by a photochemical cycloaddition to establish the cyclobutane core. Science , this issue p. 676