Organotin halides reactions

By reaction with the appropropriate aryl halides can be prepared a variety of aryltin compounds that are not accessible from the reactions involving arylmagnesium halides and organotin halides (88,89) there is evidence that an aryne intermediate may be involved (90). However, for some purposes, such as the addition to carbonyl compounds, ox-iranes, and oxetanes, to give hydroxyalkyltin compounds, the Sn-Mg reagents may have advantages (see Section II,E) (91-93). 

The oldest method for the synthesis of the organotin halides is the reaction of alkyl or aryl halides with elemental tin. This reaction exhibits numerous variants and uses a wide variety of catalysts however, yields are usually unsatisfactory and the method is no longer common nowadays. 

Dimethyltin dichloride can be synthesized from methyl chloride, tin(II) chloride and molten tin. The reaction proceeds in high yields in NaAlCLt melt359. High yields in tri-organotin halides are also obtained from tin and lower alkyl halides, provided an equimolar amount of halide is added to the reaction medium360. 

Redistribution reactions are considered as quite important for the preparation of alkyltin halides having mainly identical alkyl groups. Actually, the redistribution reactions are halogenation reactions of organotin halides by SnX4 (X = F, Cl, Br, I). 

Organotin halides are commonly prepared by the Kocheshkov redistribution reaction, where an organic group on tin (e.g., in SnR4) exchanges (reversibly) with a halide group on tin (e.g., in SnCLt).64 Two recent examples are shown in Equations (125) and (126). The first reaction exploits the high reactivity of the Sn-Me bonds, and the second... 

Reaction conditions Aqueous solutions of cotton (0.100 g 0.62 moles) with bisethylenediamine copper (II) hydroxide to give 25 ml solution are added to rapidly stirred (about 20,500 rpm no load) carbon tetrachloride (25 ml) solutions containing the organotin halide at about 25°C, 30 secs stirring time. 

A very versatile preparation seems to be the elimination of organotin halides in the reaction of organostannyl-organosilylcyclopentadienes with metal carbonyl halides. This reaction is very selective and only Sn—C bonds are cleaved with formation of 7)5-cyclopentadienyl complexes (7) ... 

Reaction of fluorinated alkenyl Grignard reagents or lithium reagents with organotin halides has been utilized for the preparation of fluorinated alkenyl tin reagents [111, 182-184]. Recently, a novel, general and convenient method has been developed for the preparation of a variety of fluorinated alkenylstannanes... 

It is known that the geometries of the reactants play an important role in the regio-and stereochemical outcome of radical reactions since they are commonly involved in early transition states. Previous attempts to affect rotamer populations during the reaction included, among others, control of temperature and addition of a Lewis acid. It was recently reported75 that organotin halides, common byproducts of radical reactions, act... 

The formation of pentacoordinated stannates 62a and 62b has been detected in the hydrolysis of the organotin halide complexes with phosphoryl ligands containing aliphatic amino group in the ligand. The tentative reaction scheme is shown in equation ll282. 

Different stannocanes may be prepared by the reaction of organotin halides or SnHaLj with a snspension of disodinm diolate in THF and disodinm dithiolate in toluene and ethanol or with free dithiols in CHCI3. These reactions yield... 

The direct reaction of tin (as foil, powder, or alloy) with organic halides has been used to produce organotin halides. Catalysts and promoters are required for all but the most reactive organic halides MePh3PBr and KI were used as catalyst and promoter, respectively, for the formation of... 

Reactions of tin(IV) halides or organotin halides with organic derivatives of more electropositive metals provide the most important general synthetic routes to carbon-tin bonds (equation 6). The most frequently used R -M compounds are those of magnesium and lithium, with sodium, zinc, and aluminum having a more limited use. Some examples of these reactions are given in equations (7-9). 

Organotin halides can also be obtained from oxides or hydroxides on reaction with hydrogen halides (or ammonium halides) (equation 61) and from tin-tin bonded species on reaction with halogens (equation 62). 

The Kocheshkov redistribution reaction between tetra-organotins and tin(rV) halides, in appropriate mole ratios, is a general method of synthesis of organotin halides (equations 59 and 60). It is a particularly useful reaction, since it is difficult to control the alkylation of SnX4 by organolithium or Grignard reagents to the desired extent. 

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