Intramolecular 1,3-dipolar nitrone and nitrile oxide cycloaddition of 2-and 4-O-allyl and propargyl glucose derivatives: a versatile approach to chiral cyclic ether fused isoxazolidines, isoxazolines and isoxazoles
Metadata of CSIR Papers
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| Title |
Intramolecular 1,3-dipolar nitrone and nitrile oxide cycloaddition of 2-and 4-O-allyl and propargyl glucose derivatives: a versatile approach to chiral cyclic ether fused isoxazolidines, isoxazolines and isoxazoles
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| Creator |
Ghorai, S
Mukhopadhyay, R Kundu, AP Bhattacharjya, A |
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| Subject |
Chemistry, Organic
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| Description |
2-O- and 4-O-Allyl and -propargyl glucose and the corresponding oxime derivatives were prepared from readily available glucose dithioacetals. Intramolecular 1,3-dipolar cycloaddition of the N-benzyl and N-methyl nitrones of the above acyclic 2-O-allyl glucose derivatives led to the diastereoselective formation of chiral isoxazolidines incorporating the tetrahydrofuran ring. The EI mass spectra revealed a characteristic cleavage of the C-alkyl group adjacent to the furan oxygen atom. An enantiopure trisubstituted tetrahydrofuran was obtained by the reductive cleavage of the isoxazolidine ring of one of the cycloadducts. In contrast, the nitrile oxide cycloaddition of the 2-O-allyl derivatives afforded diastereomeric mixtures of the corresponding dihydroisoxazolines, the stereochemistry of which was tentatively assigned on the basis of the principle of optical superposition. The exclusive formation of a tetrahydrofuran ring from pentaallyl nitrone or nitrile oxide demonstrated the preferred formation of a five-membered ring to that of six or seven-membered rings. The nitrile oxide generated from a 3,4,5,6,7-pentaallyloxy-1-nitroheptane derivative obtained from pentaallylglucose underwent diastereoselective cycloaddition to give an isoxazoline fused to a pyran ring. Enantiopure isoxazoles containing tetrahydrofuran and oxepane rings were also prepared in good yields by the nitrile oxide cycloaddition of the 2-O- and 4-O-propargyl derivatives. (c) 2005 Elsevier Ltd. All rights reserved.
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| Publisher |
PERGAMON-ELSEVIER SCIENCE LTDOXFORDTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND
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| Date |
2011-09-20T12:11:57Z
2011-09-20T12:11:57Z 2005 |
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| Type |
Article
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| Identifier |
TETRAHEDRON
0040-4020 http://hdl.handle.net/123456789/14056 |
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| Language |
English
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