Oxonium ion-mediated synthesis of 4-substituted spiro-isoxazolines

TETRAHEDRON LETTERS

卷:50

Article

McClendon, Eric¹  Omollo, Ann O.¹  Valente, Edward J.²  Hamme, Ashton T., II¹ 

[1] Jackson State Univ, Dept Chem, Coll Sci Engn & Technol, Jackson, MS 39217 USA

[2] Mississippi Coll, Dept Chem & Biochem, Clinton, MS 39058 USA

关键词: Intramolecular cyclization;    Cycloaddition;    Stereoselectivity;    Regioselectivity;    Heterocycles;    Spirocycles;   

DOI  :  10.1016/j.tetlet.2008.11.053

来源: Elsevier

【 摘 要 】

The stereoselective synthesis of 4-bromo-spiro-isoxazolines was achieved in one step through the bromination of various isoxazoles that contain a pendant alcohol or carboxylic acid functional group. Isoxazole bromination leads to a bromonium ion intermediate, which opens either by neighboring oxygen lone pair electrons or by intramolecular nucleophilic attack. Single X-ray crystal data provide evidence that the two Contiguous stereocenters of the spiro-isoxazoline are formed by the anti intramolecular attack of the nucleophile relative to bromine, since there is air anti stereochemical relationship between the spirocyclic ring oxygen and the bromine atom. Published by Elsevier Ltd.

【 授权许可】

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