ISSN:
0025-116X
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
As a model reaction for the homogeneous cationic polymerization of vinyl ethers, cis-ethyl vinyl ether-β-d (1a) was reacted with 1,1-diethoxyethane in presence of BF3O(C2H5)2 as a catalyst. The steric structures of the adducts, mainly 1,1,3-triethoxybutane-2-d (3a) and 1,1,3,5-tetraethoxyhexane-2, 4-d2 (4a, equivalent to the dimer) were determined by means of 1H NMR spectroscopy, taking into account the conformational characteristics based on energy calculation. The predominant stereoisomer of 3a was proved to be the erythro-form. The assignments of the methylene proton resonances to erythro- and threo-configurations were applied to the analysis of the spectra of 4a which enabled us to elucidate the molecular aspects of the opening of the double bond and the mode of approach of the monomer to the cationic reactive site. It was also concluded that the stereospecific reaction might be attributed to the repulsive forces between the ethoxy group of vinyl ether and that of the carbonium ion derived from the acetal.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/macp.1982.021830609
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