Synthesis 2007(15): 2337-2342  
DOI: 10.1055/s-2007-983772
PAPER
© Georg Thieme Verlag Stuttgart · New York

Biomimetic Synthesis of Fused Bispyran: Lewis Acid Effects on Oxacyclizations­ of Polyepoxides

Rongbiao Tonga, Frank E. McDonald*a, Xikui Fangb, Kenneth I. Hardcastleb
a Department of Chemistry, Emory University, Atlanta, GA 30322, USA
b X-ray Crystallography Laboratory, Emory University, Atlanta, GA 30322, USA
Fax: +1(404)7276586; e-Mail: fmcdona@emory.edu;
Further Information

Publication History

Received 27 February 2007
Publication Date:
12 July 2007 (online)

Abstract

The biomimetic synthesis of fused bispyran via Lewis acid mediated tandem oxacyclization of a 1,4,7-polyepoxide is explored. The nature of the Lewis acid promoter is critical for the endo-regioselectivity of epoxide cyclization, although anomalous apparent retention of stereochemistry is observed at some reactive centers.