Total synthesis of (-)-cylindrocyclophane A facilitated by C-H functionalization

(-)-Cylindrocyclophane A is a 22-membered C₂-symmetric [7.7]paracyclophane that bears bis-resorcinol functionality and six stereocenters. We report a synthetic strategy for (-)-cylindrocyclophane A that uses 10 C-H functionalization reactions, resulting in a streamlined route with high enantioselectivity and efficiency (17 steps). The use of chiral dirhodium tetracarboxylate catalysis enabled the C-H functionalization of primary and secondary positions, which was complemented by palladium-catalyzed C(sp²)-C(sp²) cross-couplings, resulting in the rapid formation of the macrocyclic core and all stereocenters with high regio-, diastereo-, and enantioselectivity. The use of a late-stage palladium-catalyzed fourfold C(sp²)-H acetoxylation installed the bis-resorcinol moieties. This research exemplifies how multilaboratory collaborations can produce substantial modernizations of complex total synthesis endeavors.