Total synthesis of riccardin C and (±)-cavicularin via Pd-catalyzed Ar–Ar cross couplings

Riccardin C, a specific LXRα agonist, is a representative macrocyclic bisbibenzyl-type natural product. As part of our synthetic studies on macrocyclic bisbibenzyls, the synthesis of riccardin C and its analog cavicularin was examined. The total synthesis of riccardin C was accomplished via a Pd-catalyzed intramolecular Suzuki–Miyaura coupling as the key macrocyclization step. This synthetic strategy was also extended in the synthesis of (±)-cavicularin, which was then attained by constructing the dihydrophenanthrene moiety using a Pd-catalyzed Ar–Ar coupling reaction.