Use of iodoacetylene as a dipolarphile in the synthesis of 5-iodoisoxazole derivatives.
Iodoacetylene 1 was prepared in situ from the reactions of ethynylmagnesium bromide or tributyl(ethynyl)tin with iodine. It was used as a dipolarphile in the [2 + 3] cyclization reaction with 1,3-dipolar nitrile oxide derivatives to produce 2-(5-iodoisoxazol-3-yl)pyridine 2 and 3-(4-fluorophenyl)-5-iodoisoxazole 8 in good yield (70-90%). Subsequently, several 5-substituted isoxazole derivatives 3 were obtained by Pd-catalyzed reactions. [reaction: see text]
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D-45L, Chemical Process Research, Global Pharmaceutical Research and Development, Abbott Laboratories, North Chicago, IL 60064-4000, USA.
Grieme
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Sharma
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Raje
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Morton
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King
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