Iodosilanes

The Pd(0)-catalyzed addition of trimethylsilyl iodide to an alkyne, followed by capture with alkynylstannane, affords the stereo-defined enyne 186. The reaction is explained by the oxidative addition of iodosilane, the insertion of an alkyne to generate the vinylpalladium 185, and the capture of 185 with the alkynylstannane 184[102]. 

Other specialty silanes used in microelectronic apphcations include dichlorosilane and disilane. Trihromosilane [7789-57-3] iodosilanes, and trisilylamine [13862-16-3] are of interest for microelectronics in low temperature deposition technologies. 

The iodosilane (Me3Si)3CSiPhHI is hydrolyzed readily in 1/1 v/v H20/acetone or 6/1 v/v dioxane/water to give (Me3Si)3CSiPhHOH (84),... 

Treatment of highly sterically hindered iodosilanes with a silver salt in a solvent containing water has also been used successfully to prepare bulky silanols (Scheme 6). The introduction of the OH group seems to occur not only by hydrolysis of the silyl perchlorates formed, but also by reaction of the bridged silicocationic species that are formed as intermediates in this type of reaction (62). The reaction... 

Another route to immobilising an organorhenium (Vll) oxide derived from MTO on the surface of an iodosilane-modified MCM-41 was applied (Scheme 16). 

Scheme 16 Immobilisation of trioxorhenium(VII) derived from MTO on an iodosilane-modified MCM...

The position of iodosilane and iodotrimethylsilane in the heavy salt conversion series1,2 is such that iodosilane and its methylated analogues may be used as sources for the [(CH3) SiH3. ] - (n = 0-3) groups in the preparation of a wide variety of silicon halides 3 pseudohalides, 6 chalcogenides,s,7,s and group V derivatives.9... 

Iodosilane has been prepared by the cleavage of phenylsilane10 or chloro-phenylsilane11,12 with hydrogen iodide, and by the reaction of monosilane with hydrogen iodide in the presence of a catalytic amount of aluminum triiodide.4 The latter method has been extended to prepare the methylated iodosilanes.5,13 Iodotrimethylsilane has also been prepared by the cleavage of trimethylphenyl-silane with iodine.14... 

We describe herein the synthesis of iodosilane by the reaction of phenylsilane with hydrogen iodide and the preparation of the methylated iodosilanes, namely (CH3) SiH3 I (n = 0-3), by the reaction of the parent hydride with hydrogen... 

Disilathianes, for example (SiH3)2S and [(CH3)3Si] 2S, have been prepared by several routes, namely, the reaction of iodosilane with silver8 and mercuric2 sulfides halosilanes with lithium sulfide,7 [NH4]SH,9 and [Me3NH]SH7 disilaselenane with H2S10 and trisilylphosphine with sulfur.10 Recently, the synthesis of hexamethyldisilathiane, [(CH3)3Si] 2S, was described from the protolysis of l-(trimethylsilyl)imidazole with H2S and from the dehydrohalogen-ation of chlorotrimethylsilane and H2S with a tertiary amine.11 Both of these methods require about 18 hours. 

The syntheses of disilathiane and its methylated analogues by the reaction of mercuric sulfide with gaseous iodosilanes is described here in detail. The procedures are convenient, take about 2 hours, and are well suited to small-scale vacuum-line techniques, using a minimum of special appartus. The yields are in the range of 90-95%. 

The cleaveage of phenylsilane with hydrogen iodide also provides of iodosilane (based on details given in Reference 15). 

Thiocarbonyl fluoride has also been prepared by reaction of bis(trifluoromethyl-thio)merkury and iodosilane (5i). The first product formed is trifluoromethyl-thiosilane, which spontaneously decomposes to thiocarbonyl fluoride and fluorosilane. 

EPOXIDES Alumina. r-Butyldimethyl-iodosilane. n-Butyllithium-Magnesium bromide. Cyclohexylisopropylamino-magnesium bromide. Dialkylaluminum amides. lodotrimethylsilane. Lithium l-a,a -dimethyldibenzylamide. Nafion-H. Organoaluminum compounds. Pyri-dinium chloride. Raney nickel. Tti-fluoroacetyl chloride, lrimethylsilyl-acctonitrile. Tris(phenylscleno)borane. Zinc iodide. 

In the case of mixed alkyl aryl esters the iodosilane reacts almost exclusively with the alkyl group. Similarly in the case of mixed alkyl silyl esters, the alkoxyl group is replaced by iodine. 

In summary, this procedure will be most effective with an anion of high nucleophilicity, an iodosilane of low steric requirements, and a nonpolar solvent. Reactions usually begin at low temperatures, although long shaking at room temperature may be needed for completion. The method can be capricious, and occasionally a familiar system may yield no product at all, with no obvious explanation. Nevertheless, it has considerable extra potential, particularly for the synthesis of silicon derivatives of polynuclear metal carbonyls. 

This variant of the normal route using alkali metal salts (Section II,A) depends on the fact that metallic thallium reacts smoothly with some metal carbonyls to give T1M(C0) species. These T1(I) compounds are slightly soluble in hydrocarbons and react readily with iodosilanes (8, 121) ... 

There are many instances of the formation of simple adducts between silicon-transition-metal compounds and Lewis bases (Table XIII), corresponding to mode 3 in Fig. 2. Compounds with SiH3 groups react particularly readily, in the same way that iodosilane has long been known to form adducts such as HaSil nNMe3 (n = 1,2) (36, 40, 84). 

The authors evidenced, using a methoxylated silica as a substrate, that at these temperatures no reaction occurs of the halogenosilanes with the siloxane bridges of the silica. No pretreatment temperature was mentioned, however. Therefore we cannot exclude a small reaction of the bromo- or iodosilanes with the siloxane bridges of the silica, thermally pretreated at high temperatures. 

Almost all acyclic chloro-, bromo-, and iodosilanes react with almost all nucleophiles by the Siq2-Si mechanism which leads to inversion of configuration at silicon. For example, the homochiral chlorosilane depicted in Equation Si 1.1 reacts with a range of nucleophiles including ethyllithium with clean inversion of configuration. 

Physical data and chemical shifts for the important bromo- and iodosilanes are given in Table 4. 

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