Bildung siliciumorganischer Verbindungen. 97. Über den Einfluß der Si-Substituenten (Me,Cl) auf Bildung und Reaktion von Yliden |
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Authors: | G. Fritz W. Schick |
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Abstract: | Formation of Organosilicon Compounds. 97. About the Influence of the Si-Substituents (Me, Cl) upon the Formation and the Reactions of Ylides 1,3-disilapropanes with different grade of chlorination or methylation at the silicon atoms and containing a CCl2 group cleave the Si? P bond of Me3SiPMe2. By subsequent rearrangement ylides with ? PMe2Cl group are formed. The reactivity of the CCl2 group depends on the grade of Si-chlorination resp. Si-methylation. Si-methylation decreases the reactivity of the CCl2 group. The reaction of 1,3-disilapropanes and Me3SiPMe2 (molar ratio 1:1) runs in a sequence shown in “Inhaltsübersicht”. Ylid C is able either to react with the initial compound A forming B, or in competition decomposes forming D. Reacting Si-perchlorinated carbosilanes, the decomposition forming D is not to be observed. In Si-methylated ylides like (Me3Si)2C?PMe2? PMe2 and (Me3Si)2C?PMe2? P(Me)SiMe3 the ylid carbon atom is able to abstract a proton of the P? CH3 group resp. P? H groups of the trivalent phosphorus forming (Me3Si)2C(H)PMe2. The rearrangement is proved by deuterated derivatives. The different behaviour is due to the increased basicity of the ylid-C atom in Si-methylated phosphorus ylides. Quite the same behaviour show the phosphorus ylides of 1,3,5-trisilacyclohexane. |
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