Download full text in PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... Intramolecular double Michael reaction of the α,β-unsaturated enone ester (16), prepared from the dienone (5), stereoselectively gave the tetracyclic product (17), which was converted into the isoatisirene type compound (20). ... Part I; M. Ihara, M. Toyota, K. Fukumoto, and T. ...