- LE PROBLEME DE LA CONJUGAISON A TRAVERS UN ATOME DE SILICIUM ?-LIE DANS LES SYSTEMES SILA-2 BUTADIENIQUES
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The chemical behaviour of sila-2 butadienes, formed as transient intermediates either by thermolysis or by photolysis of various 1-vinylsilacyclobutanes, was studied with respect to hydroxylated compounds of different pKa values.Two mechanisms can explain the nature of the products obtained on the co-thermolysis of the cyclic compounds with phenol, one with 1-silacyclobut-1-ene intermediate and the other involving an allylic silicenium cation.In both hypothetical mechanisms, the 2-silabutadienes behave as a conjugated system since they lead either to cycloaddition or to (1,2)- and (1,4)-electrophilic addition.This evidence for a conjugation phenomenon through a silicon atom is supported by the calculation of the delocalisation energies of butadiene and 2-silabutadiene.
- Bertrand, G.,Manuel, G.,Mazerolles, P.,Trinquier, G.
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p. 2875 - 2880
(2007/10/02)
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