A bioinspired alkylation dearomatization reaction was developed to construct the 5/6/6 fused-spiro tricyclic core framework and spiro-quaternary carbon chiral center. The usage of this approach for assembling these natural products of spirocyclic polycyclic polyprenylated acylphloroglucinols with an octahydrospiro-[cyclohexan-1,5'-indene] core is demonstrated by the first asymmetric total synthesis of highly oxidized hyperbeanol A.