Biomimetic synthesis of fused polypyrans: oxacyclization stereo-and regioselectivity is a function of the nucleophile

…, FE McDonald, WA Neiwert, B Do, KI Hardcastle

Index: Bravo, Fernando; McDonald, Frank E.; Neiwert, Wade A.; Do, Bao; Hardcastle, Kenneth I. Organic Letters, 2003 , vol. 5, # 12 p. 2123 - 2126

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Citation Number: 54

Abstract

The stereoselectivity of Lewis acid-induced endo-regioselective oxacyclizations of 1, 4- diepoxides is dependent upon the nature of the terminating nucleophile. For instance, the tert-butyl carbonate-substituted diepoxide of 3, 6-dimethylhepta-2, 5-dien-1-ol provides a cis- fused bicyclic product, whereas the N, N-dimethylcarbamate derivative affords the trans- fused diastereomer. Stereospecific and regioselective conversion of the tertiary carbamate ...