Alkyl tetrahalides

Alkyl tin compounds react with tin tetrahalides to produce a range of products that have the general formula R SnX4 n. These compounds react with LiAlH4 to produce tin hydrides. Other aspects of the organic chemistry of tin are presented in Chapter 14. 

The method of alkylation of germanium tetrahalides in the presence of catalysts251 is more effective ... 

Addition of hydrogen halides to alkynes preparation of alkyl dihalides and tetrahalides... 

The Group IVA tetrahalides undergo Grignard reactions to produce a large number of compounds containing organic substituents. For example, alkylation reactions such as the following are quite important ... 

Treatment of N-acylated a-aminonitriles 1077 with PPh3 and a carbon tetrahalide affords 2,4-disubstituted 5-halo-17/-imidazoles 1078 in good yields. A variety of alkyl and aryl substituents (R and R ) are tolerated. A possible mechanism involves the formation of a novel seven-membered ring intermediate and then elimination of triphenyl-phosphine oxide, as illustrated in Scheme 261 <20040L929>. 

The additions of tellurium tetrahalides to olefins in the presence of alcohols proceed equally well when the tetrahalides are generated in the reaction mixture from tellurium dioxide and chlorotrimethylsilane in methanoP or concentrated hydrochloric acid/methanol. trans-2-Methoxycyclohexyl tellurium trichloride was obtained in this manner in quantitative yield . In the reactions of terminal alkenes, the TeCl3 group (from TeO and concentrated hydrochloric acid) added according to the Markovnikov rule producing 2-alkoxy-1 -alkyl tellurium trichlorides. The trichlorides were not isolated but were reduced with disodium disulfite to the ditellurium compounds, which, in turn, were converted to the tellurium trichlorides by treatment with sulfuryl chlorides. For data on these tellurium trichlorides see p. 316. The overall yields range from 15 to 70%. 

The main routes to symmetrical diorganyl tellurides involve the direct reaction of nucleophilic telluride dianions (usually as Nii Tc) with alkylating or arylating reagents. Otherwise the electrophilic tellurium tetrahalides react with aryhnagnesium reagents, giving diaryl tellurides. 

A further method often used for preparation of organosilicon compounds is a Wurtz-type synthesis in which a silicon tetrahalide is condensed with an alkyl or aryl halide by means of metallic sodium in ether or a hydrocarbon solvent 313... 

If an alkyl- or aryl-silicon halide is used in place of the silicon tetrahalide, unsymmetrical organosilicon compounds can be synthesized in this way.314... 

Since Hg(II) has a closed-shell electronic structure, it is often considered spectroscopically silent in optical and EPR spectroscopy. Recent advances in a variety of spectroscopic techniques have made this description of Hg(II) complexes obsolete. Relativistic effects tend to lower energy of the Hg 6s orbital (156), and consequently the LMCT spectra of Hg(II) tetrahalides and three- or four-coordinate alkyl thiolate complexes are distinctly different than those obtained for two-coordinate complexes. As described below, ultraviolet spectroscopy has provided details about the Hg(II) coordination in the MerR protein (202, 210). 

In addition to the carbon alkylations given above it has been found possible to alkylate atoms other than carbon with the aid of organolithium compounds. For example, the general reaction of a silicon tetrahalide with an organolithium compound has been widely used as a method for preparing organosilicon compounds (13) ... 

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