Total Synthesis of (+)-Viridianol, a Marine-Derived Sesquiterpene Embodying the Decahydrocyclobuta[ d]indene Framework

A total synthesis of the title sesquiterpene 4 is described that starts with the chiral, non-racemic cis-1,2-dihydrocatechol 10 obtained through the whole-cell biotransformation of p-iodotoluene. Compound 10 is elaborated over seven steps, including Negishi cross-coupling and intramolecular Diels–Alder (IMDA) cycloaddition reactions, to ketone 7 that engages in a photochemically promoted 1,3-acyl migration and so affording cyclobutanone 6. Compound 6 was converted over further steps into the title compound 4.We thank the Australian Research Council and the Institute of Advanced Studies for financial support. F.T. and P.L. are the grateful recipients of funding provided by the CSC of the Government of the People’s Republic of China