Reaction of benzisoxazolium cations with cyclic β-diketones

Subrahmanyam, G and Jogibhukta, M (1971) Reaction of benzisoxazolium cations with cyclic β-diketones. In: Tetrahedron, 27 (21). pp. 5229-5237.

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Abstract

Reaction of 2-ethylbenzisoxazolium fluoborate (III) with dimedone, dihydroresorcinol, 2-methyldihydroresorcinol and 2-methylcyclopentane-1,3-dione in the presence of base leads to the formation of amides VIII, XI, X and XIII respectively, via the benzoketoketenimine intermediate (IX) and an intramolecular migration. The 7-hydroxy-2-ethylbenzisoxazolium salt (IV) gives the amide (XIV) by double migration. Amides VIII, XI, X and XIII undergo intramolecular Michael reaction to furnish the benzoxazinones (XVI, XVIII, XVII and XXVI). Stereochemistry of this addition is discussed and the conformation in which the CN bond at C-1′ is attached equatorially to the cyclohexanone ring is assigned to the Spirans (XX, XXX and XXVIII). Effect of acids and bases on the amide (VIII) and the spiran (XVI) is described.

Item Type:	Journal Article
Publication:	Tetrahedron
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Department/Centre:	Division of Chemical Sciences > Organic Chemistry
Date Deposited:	11 Jun 2010 08:22
Last Modified:	19 Sep 2010 06:08
URI:	http://eprints.iisc.ac.in/id/eprint/28327

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