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Reactivity, regiochemistry, and stereochemistry of a cyclic nitrone and its α-keto derivative in 1, 3-dipolar cycloaddition reactions

✍ Scribed by Sk.Asrof Ali; Mohammed I.M. Wazeer

Book ID: 104203129
Publisher: Elsevier Science
Year: 1988
Tongue: French
Weight: 683 KB
Volume: 44
Category: Article
ISSN: 0040-4020
DOI: 10.1016/s0040-4020(01)85105-x

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✦ Synopsis

Rate constants for the cycloadditlons of 3,4.5.6-tetrahydropyridine l-oxide Q), and 3-oxo-3,4,5,6-tetrahydropyridlne l-oxide (2)Ito several mom-and disubstituted alkeoes have been determined at 36'C by H NtdR Spectroscopy.

Small soLvent effect oa the rate constant indicate the concerted nature of the reaction.

It is found that nltrooa _I. reacts slower than _I_ because of the presence of bond opposition strain In the transition state for the former nitrone.

Addition rates are influenced by the dipole moments of the uitrones.

Reactivity of these addition reactions usually follows the prediction of frontier orbital approximation.

Both the nltrones exhibit very similar regi.ochemicaI and atereochemlcal properties.

Significant secondary orbital interaction is obeerred with several electron deffcient alkanes.

However, maleic anhydride is found to undergo addition predominantly via exo mode of attack.

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