ISSN:
0170-2041
Keywords:
Cycloadditions
;
Nitrile oxides
;
Spiroisoxazolines
;
Lactones
;
Dipolar cycloadditions
;
Calculations, MNDO
;
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Benzonitrile oxide cycloadds to the C=C bond of substituted 4,5-dihydro-3-methylene-2(3H)-furanones 1a-1g. Thus, (E)-1a and (E)-1b are converted into the corresponding isoxazolinespirodihydrofuranones (4RS,5RS)-2a and (4RS,5RS)-2b, and (E)-1c is converted into a mixture of isomers (4RS,5RS)-2c and (4RS,5RS)-3c. The reactions of (E)-1d-1g yield mixtures of the corresponding diastereomeric isoxazolinespirodihydrofuranones (4RS,5RS,8RS)-2d and (4RS,5RS,8SR)-2d, (4RS,5RS)-3e and (4RS,5SR)-3e, (4RS,5RS)-3f and (4RS,5SR)-3f, (4RS,5RS)-3g and (4RS,5SR)-3g. The addition of benzonitrile oxide to (Z)-1a gives (4RS,5SR)-2a and 4a. In the cycloaddition with (E)-1a the p-tolylsulfonyloxy group in the intermediate (4RS,5RS)-2a is partially replaced by chlorine to give (4RS,5RS)-2h. - The structures of (4RS,5RS)-2h, (4RS,5RS)-3e, (4RS,5SR)-3e, and 4a are determined by X-ray analysis. The 1H- and 13C-NMR spectra of the products are discussed and the reaction course is rationalized on the basis of HOMO-LUMO energy gaps.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jlac.1993199301189
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