The synthesis of ring C also required hydroxygeranyl acetate 2. Subsequent steps were allylic oxidation (SeO, tBuOH, salicylic acid) to aldehyde 13, then carbonyl reduction (NaBH) to alcohol 14, then epoxidation (VO(acac), tBuOH) to 15, then alcohol protection (MPM trichloroacetimidate) to MPM ether 16, then radical cyclisation (titanocene dichloride, manganese, triethylborane, TMSCl, KCO) to alcohol 17, alcohol  protection (BOMCl, DIPEA) to benzyloxymethyl ether 18, acetate hydrolysis (NaOH) and Ley oxidation to aldehyde 19.