- Reaction of silicon with alcohols in autoclave
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A reaction of activated silicon with alcohols in an autoclave at 240—270 °C was studied. It was found that primary alcohols form tetraalkoxysilanes Si(OR)4 with high selectivity (up to 97%), while the secondary PriOH gave a mixture of compounds HSi(OPri)3, Si(OPri)4, HSi(OPri)2OSi(OPri)2H, HSi(OPri)2OSi(OPri)3, and Si(OPri)3OSi(OPri)3 with the predominance of trialkoxysilane (up to 67%). Carrying out the reaction under the indicated conditions has the advantage of experimental simplicity, reagent availability, high conversion of silicon, good isolated yields of products.
- Krylova,Egorov,Nefedov
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p. 260 - 266
(2017/07/11)
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- Pentacoordinate dihydridosilicates: Synthesis, structure, and aspects of their reactivity
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The reactions of H- with trialkoxysilanes provide a unique and facile entry to anionic pentacoordinate dihydridosilicates [H2Si(OR)3]-, isolated as stable crystalline products in the case of bulky R groups (R = i-Pr, s-Bu, c-C6H11). Their dynamic behavior (R = i-Pr and s-Bu) has been investigated by 29Si and variable-temperature 1H NMR. Intramolecular exchange of H atoms between axial and equatorial sites is indicated and was found to be significantly dependant on the nature of the solvent. Compared to HSi(OR)3, K[H2Si(OR)3] are versatile reagents: (1) the silicon atom is an electrophilic center and this leads to nucleophilic displacements of the alkoxy groups with Grignard reagents and organolithiums; (2) they are able to reduce very easily carbonyl derivatives to alcohols without any catalyst; (3) they react with primary halides through an ionic mechanism leading to the alkane; (4) the reaction with benzylic halides is more complex and affords the dimer as the major product, the formation of which can be explained by a SET process; (5) the ability to donate one electron is confirmed in the reaction with Cp(CO)2FeI and by direct ESR observation of stable radical intermediates.
- Corriu, Robert J. P.,Guérin, Christian,Henner, Bernard J. L.,Wang, Qunjie
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p. 3574 - 3581
(2008/10/08)
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