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Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles
Published on: August 22, 2018
Total Synthesis of (±)-Baphicacanthcusine A Enabled by Sequential Ring Contractions
Paul P Sinclair1, Richmond Sarpong1
1Department of Chemistry, University of California, Berkeley, Berkeley, California, 94720, United States.
Abstract:
Reported herein is the first total synthesis of the poly-pseudoindoxyl natural product baphicacanthcusine A. The synthesis leverages the oxidative rearrangement of indoles to pseudoindoxyls to install vicinal pseudoindoxyl heterocycles in a diastereoselective manner. Key steps include an acid-mediated cyclization/indole transposition, two diastereoselective oxidative ring contractions, and a site-selective C-H oxygenation. The synthesis of the oxidation precursors was guided by recognition of an element of hidden symmetry. This work provides a foundation for the chemical synthesis of other poly-pseudoindoxyl alkaloids.
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