Synthesis of C(3) Benzofuran-Derived Bisaryl Quaternary Centers:  Approaches to Diazonamide A

Abstract

[reaction: see text] 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.