Triphenyltin halides

The reaction may be viewed as an analog of the reaction of a stronger acid with the salt of a weaker acid. Here the stronger acid, HX, liberates the weaker acid, RH. If the original organometallic system is moderately reactive and has several carbon-metal bonds, conditions can usually be found which lead predominantly to a stepwise cleavage of these bonds. An illustration is the preparation of either triphenyltin halide or diphenyltin... 

These problems can be partially solved using triphenyltin halide as cocatalyst in PT-catalyzed fluorination (68). Thus when to a suspension of KF in an aprotic solvent catal3d ic amounts of Q+X and triphenyltin fluoride are added, a soluble TAA salt of complex hypervalent Ph3SnF2 anion is formed. The anion is a mild, practically nonbasic source of fluoride anion thus, the substitution proceeds satisfactorily according to equations 144a and 144b. 

Yield given is that for triphenyltin halide yield of reduction product not determined. 

Other unsaturated triphenyltin halides are compiled in Table I32. Functionally substituted unsaturated triorganotin halides are listed in Subsections if.1.1.6.1 and if. 1.1.6.2. Table I32 is on page if82. 

Displacement of secondary allyl halides is satisfactory for the formation of symmetric allylstannanes, e.g., ( )-tributyl(l-mcthyl-2-butcnyl)stannane17, but can give 1,3-rearranged products in other cases, e.g., from 3-chlorobutene and trimethyltin reagents14 lS. Allylic cyclohexenyl chlorides react with triphenyltin lithium with clean inversion and little 1,3-transformation19,20. 

One of the largest commercially used Grignard reagents is phenylmagnesium chloride. Millions of kg per year of this Grignard react captively with inorganic halides. Some examples of these products are triphenylphosphine, triphenyltin hydroxide, sodium tetraphenylborate, and triphenyl an tim ony. 

The reaction of Pl SnLi with selenium in THF at room temperature led to the lithium triphenyltin selenide, which had been trapped by reaction with metal-14 halides (Scheme 18)2. 

Selenides are also nucleophilic and produce isolable selenonium salts (9) when treated with alkyl halides. They are easily oxidized to selenoxides (10) and further to selenones (11) under more forcing conditions (see Section 4). Reduction of selenides to the corresponding hydrocarbons is most conveniently achieved with nickel boride,or with tri-n-butyl- or triphenyltin hydride under radical conditions. " Other reagents for reductive deselenization include Raney nickel, lithium triethylborohydride, and lithium in ethylamine (Scheme 4). Benzylic selenides undergo radical extrusion reactions under thermal or photolytic conditions to produce... 

CV studies indicate that Ph3SnY, where Y = Cl, OTf, OCHO, SnPh3, do not serve as a source of the triphenyltin radical because in these instances the radical is generated at potentials where it is either oxidized or reduced [19]. Reaction of the triphenyltin radical with an alkyl halide or a disulfide produces a carbon- or a sulfur-centered radical, respectively. Use of the latter transformation in conjunction with a subsequent intramolecular cyclization onto an alkene is nicely illustrated by the conversion of /6-lactam 62 to the cephalosporin analog 63. 

Triphenyltin lithium is synthesizedfrom organotin halides with xs Li metal in tetrahydrofuran (THE) ... 

For example, triphenylpentafluorophenyltin can be prepared from triphenyltin penta-fluorobenzoate in refluxing pyridine 130 the alternative route via pentafluorophenyl-magnesium halide gives a relatively poor yield because of the instability of the Grignard reagent. 

A number of stannyl-zinc and -cadmium compounds have been prepared by reaction of a tin-alkali metal compound with a zinc or cadmium halide, or a tin hydride with an alkyl-zinc or -cadmium compound. The coordination of a ligand such as a triphenyl-phosphine, TMEDA, or bipyridyl, or a solvating solvent such as DME, both enhances the nucleophilicity of the alkyl group in the alkylmetallic compounds and stabilises the stannylmetallic product. Thus triphenyltin hydride reacts with diethylzinc or diethylcad-mium in pentane or benzene with separation of metallic zinc or cadmium, but with a preformed complex, or in a coordinating solvent, the distannylmetallic compound is formed (e.g. equation 19-32). 

Organotin hydride reductions of a variety of polycyclic halides containing three-membered rings have been studied, including the stereoselectivity in the triphenyltin hydride reduction of 6jS-chloro-3,5-cyclocholestanes, Tributyltin hydride reduction of both syn- and anti-1-chloro-2-methylnortricyclene (35) afforded cn fo-5-methylnorbornene (36) as the major product, with very little of the e.w-isomer. ... 

Fluoride ions can be separated from other halides by extraction into CHCI3 with the use of triphenyltin chloride [18]. 

Reduction of aryl halides. Aryl halides have generally been considered to be resistant to hydrogenolysis by lithium aluminum hydride. However, Karabatsos and Shone2 found that certain aromatic halides are reduced by the reagent in diglyme at 100°. The order of reactivity is 1 > Br > Cl > F. These chemists concluded, however, that triphenyltin hydride is superior for this purpose. 

Hexaphenylditin has also been obtained by electrolysis of a methanol solution of triphenyltin chloride, the product being produced at the cathode 226). Other triorganotin halides have been electrolyzed in aqueous isopropanol, but the ditin compounds thought to be produced were not isolated 227). 

Triphenyltin hydride Carboxylic acid esters from 2 carboxylic acid halide molecules... 

Since potassium salt of triphenyltin difluoride anion is soluble in some solvents, eg, sulfolane, PhsSnF can act as sole PT catalyst for fluorination of alkyl halides and sulfonates (eqs. 145a, 145b, and 146). 

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