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Vinyl and Alkynyl Pyrimidines as Michael Acceptors:  An Approach to a Cylindrospermopsin Substructure

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journal contribution
posted on 11.08.2000, 00:00 by Jane F. Djung, David J. Hart, Erick R. R. Young
Vinyl pyrimidine 9 and alkynyl pyrimidine 24 undergo base-mediated intramolecular conjugate addition reactions in which a carbamate and a urea, respectively, behave as nitrogen nucleophiles. The cyclic carbamate derived from 9 was converted to 11 via a metalation−oxidation reaction in which 2-phenylsulfonyl-3-phenyloxaziridine behaves as a hydroxylation reagent. The cyclic urea derived from 24 was converted to cylindrospermopsin substructure 30 using dimethyldioxirane to introduce the C7 hydroxyl group.