Synthesis of C(3) benzofuran-derived bisaryl quaternary centers: Approaches to diazonamide A

[GRAPHICS] Two complementary strategies for the synthesis of the diazonamide A bisaryl quaternary center are described. The first strategy relies upon an extremely facile tandem cyclopropanation/ring opening sequence, which has proven amenable to chiral catalysis to provide enantioenriched material. The second strategy relies upon a more concise alkylation route ideal for material advancement.