Tetraalkyltin compounds

The alkylation can also be accompHshed using tetraalkyltin compounds. Alkyldiiodostibines are formed in about 20% yield via the interaction of alkylmagnesium iodides and antimony trichloride (67). Dialkylchlorostibines are obtained in good yields by the cleavage of tetraalkyldistibines using sulfuryl chloride (91) ... 

The synthesis and properties of the tin-carbon bond were reviewed in reference (35). Three recent volumes of Gmelin, written by H. Schumann and I. Schumann, comprehensively cover the literature, up to the end of 1973, on tetraalkyltin compounds R Sn (36), RaSnR (37), and RtSnR, RjSnR R", and RR SnR"R " (38), and are invaluable sources of reference. 

The use of organotin compounds for the preparation of organometallics and organometalloids appears to be quite versatile.9 For example, alkyltetrafluorophosphoranes have been obtained from tetraalkyltin compounds and phosphorus(Y) fluoride,10 phenylmercury(II) chloride from tetraphenyltin and mercury(II) chloride,11 and divinylbromoarsine from ( -C4H9)2-Sn(CH=CH2)2 and arsenic (III) bromide.12... 

Wong and coworkers37 studied a series of both symmetrical and unsymmetrical tetraalkyltin compounds with different alkyl substituents, focusing their attention on the effect of these on the ionization energy of the highest occupied MOs. It is useful to recall the type of molecular orbitals deriving from the triply degenerate HOMO in the symmetrical R4M (local symmetry Td) upon substitution of one or more R ... 

Tetraalkyltin compounds are prepared by treating R3A1 with Sn(OAc)4 (R = Ci ig) in THF111. 

The various tetraalkyltin compounds were then identified and quantitated by GC MS and gas chromatography-atomic absorption analyses. The results indicated that tin(II) chloride in the simulated sea water was converted into methyltin trichloride and dimethyltin dichloride. The tin(IV) chloride, on the other hand, only formed methyltin trichloride. No trace of trimethyltin chloride was found from either tin(II) or tin(IV). The maximum amount of methyltin trichloride was formed near pH = 6 and at a salinity of 28%. The rate expression for the reaction is... 

The first instance of SFC coupled to ICP-MS was reported by Shen et al. [127] for the speciation of tetraalkyltin compounds. Liquid C02 was used as the mobile phase and the SFC column was completely inserted through the transfer line and connected to a frit restrictor (Fig. 11). The restrictor was heated to approximately 200°C by a copper tube inserted into the ICP torch. Tetramethyltin (TMT), tetrabutyltin (TBT), tetraphenyltin (TPT), tributyltin acetate... 

At the time the chemistry of (OC)9Co3CCO+PF6 was being developed (27, SO), another route to this novel acylium ion was found in these laboratories (31, 32). This discovery was a result of our intention to adapt the Friedel-Crafts synthesis of benzylidynetricobalt nonacarbonyl complexes of Dolby and Robinson (15) to the preparation of alkyl derivatives of methylidynetricobalt nonacarbonyl, whose general preparation was not well in hand. The reaction chosen for investigation was the aluminum chloride-induced interaction of tetraalkyltin compounds with ClCCo3(CO)9 In analogy to a known ketone synthesis (33),... 

Tetraalkyltin compounds (R4Sn) react with tetracyanoethylene (TCNE) to form an insertion product [33] (Eq. 91). 

A quasi-linear correlation of log/c or AG with the ionization potentials of the electron donors as observed in the FeL3 - + reactions is predicted by Marcus theory for outer-sphere electron transfers. Accordingly, the free-energy dependence of AG can be satisfactorily simulated with the Marcus equation (Eq. 90), taking a (constant) value of A = 41 kcal mol as reorganization energy for all tetraalkyltin compounds (see Figure 19A) [32]. 

Methyl, ethyl, propyl, and butyl halides are reduced at lead and tin cathodes to produce, respectively, the corresponding tetraalkyllead and tetraalkyltin compounds in excellent yield. Bismuth, gallium, indium, and thallium can be employed to prepare a variety of organometallic compounds. Feoktistov [2] and Hawley [4] have summarized many of these electrosyntheses. 

The preparations of tetraalkyltin compounds are described in Chapter 4. They are usually colourless liquids or solids which are stable to air and water the m.p. or b.p. of some representative examples is given in Table 5-1. 

A number of tetraorganotin (though not yet tetraalkyltin) compounds in which the chirality is centred on the tetrahedral tin centre have been optically resolved by either (a) recrystallisation of the diastereoisomers which are formed with an optically active reagent (e.g. equation 5-1 and 5-2), or (b) by an asymmetric synthesis (e.g. equation 5-3), or (c) by chromatography on microcrystalline cellulose acetate (e.g. equation 5-4).2 These compounds are listed in Table 5-2, where the group which is involved in an asymmetric synthesis is printed in italics. In only a few cases is the optical purity known. 

Rather little work has been carried out on the mechanisms of these protiodealkylation reactions. The reaction with HCI in methanol or methanol/benzene is second order. Stereochemical studies are restricted by the fact that, though tetraalkyltin compounds with chirality centred on tin are optically stable, the reaction products R3SnX are not, and compounds with chirality centred on the a-carbon atom in R would have to have the structure RR R"CSn or RR CDSn for the product to be configurationally stable. The only examples appear to be that the reaction of trimethyl(l-methyl-2,2-diphenylcyclo-propyl)tin with HCI or HBr,30 and of cis- and /ra .v-5-methyl- or -5-t-butylcyclohexyl-triisopropyltin with deuteriotrifluoroacetic acid31 proceed with complete retention (equations 5-27 and 5-28), which would be compatible with either an SE2(open) or SE2(cyclic) mechanism. 

The SN2(Sn)(coord) mechanism, however, is familiar in the synthetically important Sn/Li transmetallation reaction that occurs between tetraalkyltin compounds and alkyl lithiums. This process is discussed in Section 19.1.1, and its applications in synthesis in Section 22.1. 

Free radical reagents usually react with tetraalkyltin compounds at a hydrogen centre in one of the alkyl ligands to give a stannylalkyl radical. P-Stannylalkyl radicals prepared in this way can then undergo P-scission to break the Sn-C bond. Thus the photolysis of di-t-butyl peroxide in the presence of trimethylisobutyltin and ethylene or an alkyl bromide, gives rise to the ESR spectrum of the P-stannylethyl radical or of the alkyl radical respectively, which are formed by the sequence of reactions shown in equations 5-38.50... 

Alkylation of 2,6-disubstituted pyryliums has been achieved using tetraalkyltin compounds in the presence of UV light the initial adducts are re-oxidised in situ to produce 4-substituted pyrylium salts. ... 

The reaction proceeds with higher yield and under more simple conditions if the RjSnXj compound is used as the original substance and one part of the tetraalkyltin compound is reacted with SnX and recycled ... 

The manufacture of OTC involves a two-step reaction. The first step can be achieved in a number of different ways and involves reaction of tin tetrachloride (SnCU) with a suitable reagent to produce various tetraalkyltin compounds (ILjSn). In the second step, It Sn reacts with SnCU in a redistribution reaction to form less alkylated organotin chlorides such as R3SnCl, R2SnCl2, or RSnCls. From these products, various other tin derivatives can be produced. A direct reaction scheme is also possible whereby the organotin halides can be synthesized by a reaction between tin metal or alloy and alkyl halides. 

Tetraalkyltin compounds having the chiral alkoxy group at the a-position undergo the Pd-catalyzed cross-coupling reaction of acyl chlorides with complete retention of the configuration (Scheme 7).P9],i40]... 

Dermal Effects. Dialkyltin compounds, especially dimethyltin and diethyltin dichloride, are dermal irritants but several of them, like dibutyltin diacetate, dilaurate, maleate, and oxide, are not [42], Tributyl- and trimethyltin compounds are not allergic dermal and conjunctival irritants but are responsible for acute bums appearing several hours after the dermal contact [42]. The lesions last several days, and consist of follicular inflammarion, pruritis, and minute pustules that dry after 2 or 3 days. Recovery takes a week. The hair doesn t seem to be affected. Subacute contacts are responsible for pruritis and scratching lesions, reddening of the skin, and sticky skin. Lesions affect the lower abdomen, thighs, groin, and perineum. Tetraalkyltin compounds applied on the skin have never produced any effect [42]. 

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