Diverging Pathways to Topologically Complex Polycyclic Bis-acetals and Their Ring System Interchange

Carbinol-tethered octalin-diols (1), which differ only by the C11 configuration at the angular position, were transformed selectively to three types of structurally unrelated original scaffolds such as unsymmetrical octahydroanthracenes (5/7), furofuranes (6), or spirans (8/9) via a two-step protocol. The 11S* configuration ensures a C13–C4 Friedel–Crafts type C–C bonding (through an unprecedented oxidative cleavage-triggered domino process) while the 11R* configuration allows for a C13–C2 Marson-type Friedel–Crafts C–C bonding (through a nucleophilic acetal opening).