Stereocontrolled and Efficient Total Synthesis of (−)-Stephanotic Acid Methyl Ester and (−)-Celogentin C

A highly stereocontrolled and efficient total synthesis of (−)-stephanotic acid methyl ester and (−)-celogentin C was accomplished in longest linear 14 steps (4.6% overall yield) and in 20 steps (1.6% overall yield) from l-tryptophan, respectively. Highlights of the synthesis include a tandem asymmetric Michael addition/bromination/azidation strategy for a ready access to the leucine-tryptophan moiety (Leu-Trp linkage) and an oxidative coupling reaction to form the indole-imidazole linkage.