Agariblazeispirol C (1), which has a unique steroidal skeleton, has been isolated from the cultured mycelia of Agaricus blazei (Agaricaceae). Recent work in our laboratory concerning the intramolecular Pauson-Khand reaction of exo-cyclic enynes has revealed methods for the facile construction of bi- and tri-cyclic skeletons, which can be considered promising for the stereoselective construction of BCD rings in 1.