ISSN:
0030-493X
Keywords:
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The electron impact induced decomposition of five of the title compounds with methyl, ethyl, n-propyl, n-butyl or n-pentyl groups, has been investigated in detail. The observed fragmentation can be characterized by two outstanding features: (a) interactions of the silicon centre with the ethereal oxygen atom of the methoxy carbonyl group, (b) strong directing effects of the cyclopropene ring. As a consequence of (a), the loss of a (CH3)3SiOCH3 molecule represents the main decomposition pathway of the molecular ion. It was shown to be a low energy, single dissociation step reaction, not depending on the radical site or charge localization. In spite of the rigid skeleton, ring opening does not take place during this process. As to (b), beside the β-fission, highly selective and intense δ- and ∊-cleavages of the alkyl chain have been observed following the (CH3)3SiOCH3 elimination. On the basis of energetic and kinetic considerations, these interesting reactions can be rationalized in terms of through-space interactions and intramolecular ortho substitution (cyclization) processes.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/oms.1210160505
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