M. Mickoleit, Kathleen Schmohl, M. Michalik
Apr 1, 2004
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0
Influential Citations
10
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Journal
European Journal of Inorganic Chemistry
Abstract
The reaction of the (dichloromethyl)oligosilanes R(Me3Si)2SiCHCl24a−d (4a: R = Me; 4b: R = tBu; 4c: R = Ph; 4d: R = SiMe3) with 8-(dimethylamino)-1-naphthyllithium leads to the intramolecularly donor-stabilized silenes 1a−d. Whereas 1a,b, and d were isolated as thermally stable yellow crystalline compounds, 1c could not be separated in a pure form but was characterized by NMR spectroscopy and mass spectroscopy as well as by its chemical reactivity with a variety of substrates. Dynamic 1H NMR spectroscopic studies of 1a and 1d revealed coalescence of the signals of the two CSiMe3 groups. In agreement with theoretical calculations, this effect was interpreted as the result of internal rotations about the silene double bond. These findings and the known relatively long Si=C distances for 1d, 2 and 3 help establish the ylide-like nature of the silenes prepared. Treatment of 1a−d with water produced the silanols 9a−d. Treatment of 1a,b, and d with methyl iodide caused a rearrangement of the silenes, one methyl substituent formally migrating from the coordinated dimethylamino group to the silene carbon atom producing the respective cyclic aminosilanes 11a,b, and d. As the outcome of the reaction of 1d with benzaldehyde, 2,2-bis(trimethylsilyl)vinylbenzene (14) and a mixture of the two isomers of the cyclodisiloxane 13 were obtained. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)