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Synfacts 2009(8): 0817-0817
DOI: 10.1055/s-0029-1217578
DOI: 10.1055/s-0029-1217578
Synthesis of Natural Products and Potential Drugs
© Georg Thieme Verlag
Stuttgart ˙ New York
Synthesis of (+)-Quebrachamine
Contributor(s):Philip Kocienski, Stewart EcclesE. S. Sattely, S. J. Meek, S. J. Malcolmson, R. R. Schrock, A. H. Hoveyda*
Boston College, Chestnut Hill and, Massachusetts Institute of Technology, Cambridge, USA
Design and Stereoselective Preparation of a New Class of Chiral Olefin Metathesis Catalysts and Application to Enantioselective Synthesis of Quebrachamine: Catalyst Development Inspired by Natural Product Synthesis
J. Am. Chem. Soc. 2009, 131: 943-953
Boston College, Chestnut Hill and, Massachusetts Institute of Technology, Cambridge, USA
Design and Stereoselective Preparation of a New Class of Chiral Olefin Metathesis Catalysts and Application to Enantioselective Synthesis of Quebrachamine: Catalyst Development Inspired by Natural Product Synthesis
J. Am. Chem. Soc. 2009, 131: 943-953
Further Information
Publication History
Publication Date:
23 July 2009 (online)
Key words
quebrachamine - enantioselective ring-closing metathesis - chiral molybdenum catalysts
Significance
Quebrachamine is an Aspidosperma alkaloid that is an adrenergic blocker. This synthesis is noteworthy for the highly enantioselective ring-closing cross-metathesis (G → I) using a chiral molybdenum catalyst which is stereogenic at the metal center.
Comment
The catalyst H was made by a diastereoselective desymmetrization (dr = 7:1) of a Mo bispyrrolide precursor with one equivalent of monosilyl-protected octahydrobinaphthol in benzene at room temperature. No improvement on the impressive enantiomeric ratio was seen when diastereoisomerically pure H was used.