ISSN:
0009-2940
Keywords:
1,3,4-Oxadiazin-6-ones
;
Diels-Alder reactions
;
Enol lactones
;
Lactone conformations
;
Line-shape analysis
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Cycloadditions of 6H-1,3,4-Oxadiazin-6-ones (4,5-Diaza-α-pyrones), 10 1). - Reactions of Bicyclo[2.1.1]hexenes with 6H-1,3,4-Oxadiazin-6-ones and Dynamic Effects in a Nine-Membered, Bridged, α,β-Unsaturated Enol Lactone 2)The reactions of bicyclo[2.1.1]hexene (2) and its tricyclic derivative 3 with 2,5-diphenyl-6H-1,3,4-oxadiazin-6-one (1 a) gave the 3,4-dihydro-α-pyrones 6 and 7, respectively. In contrast, the methyl phenyloxadiazinonecarboxylate 1 b and 2 afforded a mixture of the nine-membered, bridged, α,β-unsaturated enol lactone 11 and the β-lactone 12 in a ratio of about 10: 1. Olefin 3 reacted with 1 b to furnish small amounts of the bridged derivative 16 of 11 as well as the 2:1 product 14, a saturated δ-lactone. Unlike 16, enol lactone 11 reveals dynamic phenomena, which have been investigated by means of line shape analyses of the temperature dependent 13C-NMR spectra. The interconvertion of the cis- and trans-lactone conformers (11 a ⇄ 11 b), being present in a 1:2 ratio, proceeds with δH
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19911240619
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