Catalytic Asymmetric Total Synthesis of (-)-Actinophyllic Acid
Lingchao Cai1, Kui Zhang1, Ohyun Kwon1
1Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095-1569, United States.
Abstract:
Described herein is a catalytic asymmetric total synthesis of (-)-actinophyllic acid, with the key step being a chiral phosphine-catalyzed [3 + 2] annulation between an imine and an allenoate to form a pyrroline intermediate in 99% yield and 94% ee. The synthesis also features CuI-catalyzed coupling between a ketoester and a 2-iodoindole to shape the tetrahydroazocine ring; intramolecular alkylative lactonization; SmI2-mediated intramolecular pinacol coupling between ketone and lactone subunits to assemble the complex skeleton of (-)-actinophyllic acid; and an unprecedented regioselective dehydroxylation.
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