Cardenolides and bufadienolides constitute an attractive class of biologically active steroid derivatives which have been used for the treatment of heart disease in traditional remedies as well as in modern medicinal therapy.

Sesqui- and sesterterpenes of ophiobolin and fusicoccin families are important synthetic targets because of complexity of structure and potentially useful physiological activities, including anti-tumor activity. A synthesis of versatile building blocks for these terpenoids is described. Cyclopenta[8]annulene rings system with properly dislocated substituents was constructed using as key steps ring closing metathesis reaction and Wagner - Meerwein rearrangement. Ring closing metathesis reaction leading to cyclopenta[8]annulene was studied in detail.

An efficient double bond migration–ring closing metathesis reaction leading to cycloheptene derivatives is observed when specific sterically congested 1,9-dienes are treated with the Grubbs' imidazolidene ruthenium catalyst. The simultaneous use of the Grubbs' catalyst and RuClH(CO)(PPh₃)₃ facilitates the tandem bond migration–metathesis process. RuClH(CO)(PPh₃)₃ alone is capable of triggering an unactivated double bond migration that may have preparative applications.

Unsaturated ketones (7) were obtained in a reaction sequence involving BF₃-mediated addition of the alkylaryl sulphone (3) and oxiranes (4), oxidation of the hydroxy group in the adducts, and elimination of arylsulphinic acid; the C-6 functionalization had a long-range effect on the steric course of reduction of the 15-oxo group in prostaglandin intermediates.