Substitutions, Isomerizations, and Redistributions

The highly sterically hindered organosilicon iodide (Me3Si)3CSiMe2l undergoes solvolysis in methanol by an SnI process. Phenacyl bromide reacts with (arylthio)trimethylsilanes, Me3Si-SPh, to give aryl-phenacyl sulfides and bromotrimethylsilane via the formation of a five-coordinate 

The inversion at tetracoordinated silicon in nucleophilic media is well known, and is always of second or higher order with respect to the nucleophile. It is of considerable interest therefore to note one example which involves only a first-order dependence on the concentration of the nucleophile. The mechanism of inversion of compound 3 involves attack 

Alkoxyl exchange in redistribution reactions of alkyl alkoxyl silanes is catalyzed by several interhalogen compounds, notably iodine monobromide, and by iodine. Halogen exchange between alkyl halides and trimethylsilicon iodide is also catalyzed in some cases by iodine.  

Detailed stereochemical studies on substitution of some optically active silanes RsSiX by a series of p-substituted aryloxides and by allyl lithium shows, for a given leaving group, a dependence upon the ion-pair dissociation of the aryloxides. In the case of reaction with the lithium allyl. 

Compounds of this type show exceptional enhancement of reactivity in reactions such as (3). This enhancement has been attributed to inductive 

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