Chlorosilanes alkylation with

Vinyldialkylsilanes and vinyltrimethylsilane having no chlorine atoms do not undergo alkylation with benzene derivatives in the presenee of aluminum chloride but vinylchlorosilanes react with benzene to give the alkylation products. The reaetivities of vinylchlorosilanes decrease in the following order vinyl(methyl)di-chlorosilane > vinyltrichlorosilane > vinyl(dimethyl)chlorosilane. 

In the alkylation of benzene with (dichloroalkyl)chlorosilanes in the presence of aluminum chloride catalyst, the reactivity of (dichloroalkyl)silanes increases as the spacer length between the C—Cl and silicon and as the number of chloro-groups on the silicon of (dichloroalkyl)chlorosilanes decreases as similarly observed in the alkylation with (cD-chloroalkyl)silanes. The alkylation of benzene derivatives with other (dichloroalkyl)chlorosilanes in the presence of aluminum chloride gave the corresponding diphenylated products in moderate yields.Those synthetic data are summarized in Table XI. 

As shown in Table XIV, the reactivity of (trichloromethyl)silanes varied depending upon the substituent on silicon. The reactivity and yields of (trichloromethyl)-methyldichlorosilanes were slightly higher than those of (trichloroinethyl)tri-chlorosilanes in the aluminum chloride-catalyzed alkylation as similarly observed in the alkylations with (ai-chloroalkyl)silanes and (dichloroalkyl)silanes. The electron-donating methyl group on the silicon facilitates the alkylation more than the electron-withdrawing chlorine. The minor products, (diphenylmethyl)chloro-silanes, were presumably derived from the decomposition of (triphenylmethyl)-chlorosilanes. 

The reactivity of allylchlorosilanes for the alkylation of ferrocene varies depending upon the substituents on the silicon atom. Generally, the reactivity increases as the number of alkyl groups on the silicon of allylsilanes increases." Allyl(dialkyl)-chlorosilanes react with ferrocene in the presence of HfCU under mild reaction... 

The reaction of lithiated cumulenic ethers with ethylene oxide, trimethyl-chlorosilane and carbonyl compounds shows the same regiosnecificity as does the alkylation. 

The direct process is less flexible than the Grignard process and is restricted primarily to the production of the, nevertheless all-important, methyl- and phenyl-chlorosilanes. The main reason for this is that higher alkyl halides than methyl chloride decompose at the reaction temperature and give poor yields of the desired products and also the fact that the copper catalyst is only really effective with methyl chloride. 

In this section, the reactivities of organosilicon compounds for the Friedel-Crafts alkylation of aromatic compounds in the presence of aluminum chloride catalyst and the mechanism of the alkylation reactions will be discus.sed, along with the orientation and isomer distribution in the products and associated problems such as the decomposition of chloroalkylsilanes to chlorosilanes.. Side reactions such as transalkylation and reorientation of alkylated products will also be mentioned, and the insertion reaction of allylsilylation and other related reactions will be explained. 

To optimize the alkylation conditions, ferrocene was reacted with allyldimethyl-chlorosilane (2) in the presence of various Lewis acids such as aluminum halides and Group lO metal chlorides. Saturated hydrocarbons and polychloromethanes such as hexane and methylene chloride or chloroform were used as solvents because of the stability of the compounds in the Lewis acid catalyzed Friedel-Crafts reactions. The results obtained from various reaction conditions are summarized in Table IV. 

The alkylation of benzene with ((w,a -dichloroalkyl)silanes was also studied in the presence of aluminum chloride catalyst. The alkylation gave diphenylated products, (w.w-diphenylalkyl)chlorosilanes in fair to good yields (Eq. (12)). 

Dichloroalkyl)chlorosilanes undergo the Friedel-Crafts alkylation type reaction with biphenyl in the presence of aluniinurn chloride catalyst to afford 9-((chlorosilyl)alkyl)fluorenes through two step reactions (Eq. (16)). The results obtained from the alkylation of biphenyl and the cyclization reaction to 5-membered-ring product are summarized in Table XIIE... 

To examine the decomposition of (triphenylmethyl)chlorosilanes to (diphenyl-methyOchlorosilanes during the alkylations of benzene with (trichloromethyl)-... 

A.s. shown in Table XV, the decomposition of (triphenylmethyl)methyldichloro-silane did not occur at room temperature, but occurred at the reflux temperature of benzene to give (diphenylmethyl)methyldichlorosilane in 10 and 20% yields after I and 2 h reaction periods. The results indicate that the decomposition occurs in the alkylation reaction conditions of benzene with (trichloromethyl)chlorosilanes a.s observed in the decomposition of tetraphcnylmethane to triphenylmethane. ... 

Dialkoxydichloro silanes exhibit a higher nucleophilicity compared to the chlorosilanes described before. Diethoxysilyl-bis(0-alkyl)phosphonates of type 8 are formed in 90% yield besides 10% of disilylated phosphonates in the reaction of dialkyl phosphonates with dichlorodiethoxy silanes at 50-80°C. 

To get further insight into the reactivity of the metallo-silanols, condensation with diverse chlorosilanes has been studied. It offers easy and general access to the ferrio-disiloxanes 15a-d via interaction of 2a or its lithiation product 13 with alkyl-, aryl- or metallo-chlorosilanes in the presence of NEt3 (Eq.(3)). 

Pioneering work by Verbeek and Winter [12,13] showed that the reaction of alkyl- or aryl-chlorosilanes with ammonia, amines, or amides yields aminosilanes or silazanes which can be converted into polysilazanes (Eqs. 5,6). 

Aminolysis of the corresponding halides is the preferred method for the synthesis of dialkylamino derivatives of boron,1 silicon,2 germanium,3 phosphorus,4 arsenic,5 and sulfur.6 (Dialkylamino) chlorosilanes are prepared stepwise by the reaction of silicon tetrachloride with dialkylamines. This method may be utilized equally well for the conversion of alkyl- or aryl-substituted halides [e.g., (CH3) SiCl4. ] or of oxide and sulfide halides (e.g., POCl3 or PSC13) to the corresponding dialkylamino compounds. 

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