Synthesis 2010(16): 2841-2852  
DOI: 10.1055/s-0030-1258151
FEATUREARTICLE
© Georg Thieme Verlag Stuttgart ˙ New York

Enantioselective Synthesis of (+)-Polyanthellin A via Cyclopropane-Aldehyde (3+2)-Annulation

Matthew J. Campbell, Jeffrey S. Johnson*
Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3290, USA
Fax: +1(919)9622388; e-Mail: jsj@unc.edu;
Further Information

Publication History

Received 4 June 2010
Publication Date:
07 July 2010 (online)

Abstract

The asymmetric synthesis of the cladiellin diterpene natural product (+)-polyanthellin A is described. The core tetrahydrofuran was constructed using a stereospecific and stereoselective (3+2)-annulation of a donor-acceptor cyclopropane and a labile β-silyloxy aldehyde. These particular reactants necessitated the application of a new Lewis acid, MADNTf2 [(ArO)2AlNTf2], to avoid competitive elimination. Ring-closing metathesis was employed to form the oxonane ring at C3-C4 and give a functional group handle that could be elaborated to the natural product.

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X-ray crystallography was performed by Dr. Peter White. CCDC 773310 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.