Regio- and stereoselective thermal cyclo
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Navdeep K. Girdhar; M.P.S. Ishar
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Article
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2000
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Elsevier Science
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French
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Thermal cycloaddition of a-aryl-N-phenylnitrones to the C16 C17 p-bond in 16-dehydropregnenolone-3b-acetate (1) involves only the minor rotamer (E-form) of the nitrones and occurs regio-, stereo-and p-facial-selectively to afford steroido [16,17-d]isoxazolidines (3) in high yield.