Biomimetic Asymmetric Total Syntheses of Spirooliganones A and B

Biomimetic total syntheses of potent antiviral spirooliganones A and B were achieved with 396 and 296 yield, respectively, in 12 steps from commercially available materials. The synthetic strategy was inspired primarily by the biogenetic hypothesis and was enabled by two independent cascade events: (i) an unprecedented reaction involving aromatic Claisen rearrangement/o-quinone methide formation/hetero-Diels-Alder cycloaddition to construct the tetracyclic framework and (ii) phenol oxidative dearomatization/spirocydization to build the spiro-fused cyclohexadienone/tetrahydrofuran moiety.