Studies on the Rh and Ir mediated tandem Pauson–Khand reaction. A new entry into the dicyclopenta[a,d]cyclooctene ring system

A Rh-mediated tandem Pauson–Khand reaction has been developed to provide the desired diastereomer 8a in a 7:1 ratio over the undesired isomer(s), and this has been converted into the [5.8.5] system 11 to provide a potential new route to the ophiobolins.