An ew Ti III -mediated reductive epoxide-opening/ Beckwith-Dowdr earrangement process efficiently assembles the bicyclo[3.2.1]octane framework of highly oxidized grayanane diterpenoids.B yi ncorporation of aC u(tbs) 2 -catalyzed (tbs = N-tert-butylsalicylaldiminato) intramolecular cyclopropanation, ad iastereoselective oxidative dearomatizationinduced Diels-Alder cycloaddition and aM eReO 3 -catalyzed Rubottom oxidation, this approach has enabled the first total syntheses of rhodomolleins XX and XXII in 23 and 22 steps, respectively.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.