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
IR@IICB: CSIR-Indian Institute of Chemical Biology, Kolkata
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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, Subir
Mukhopadhyay, Ranjan Kundu, Asish P Bhattacharjya, Anup |
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| Subject |
Chemistry
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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.
q 2005 Elsevier Ltd. All rights reserved.
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| Publisher |
Elsevier
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| Date |
2005
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| Type |
Article
PeerReviewed |
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| Format |
application/pdf
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| Identifier |
http://www.eprints.iicb.res.in/496/1/33.pdf
Ghorai, Subir and Mukhopadhyay, Ranjan and Kundu, Asish P and Bhattacharjya, Anup (2005) 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. Tetrahedron, 61. pp. 2999-3012. |
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| Relation |
http://dx.doi.org/10.1016/j.tet.2005.01.119
http://www.eprints.iicb.res.in/496/ |
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