Dialkyl tin compounds

Upon addition of cyclopropane 1 to one equivalent of SnCl in methylene chloride at 0 °C, an exothermic reaction occurs to give 3-stannyl propionate 11 in approx. 70% yield [9, 11]. Addition of a second equiv of the cyclopropane slowly converts 11 to the dialkylated tin compounds, 12 Eq. (15). No further alkylation was observed. Chelate structures of such homoenolates implied by their spectral properties are supported by single crystal X-ray analysis [30]. 

Among organotin compounds the most widely used are various organic salts of dialkyl tin, such as diethyl- and di-n-butyltin dicaprylates, di-n-butyltin dilaurate, di-n-butyltin distearate, etc. As a rule, these compounds are obtained through tin alkylhalogenides. 

Diethyl ditellurium and bis[triethylgermyl] mercury yielded ethyl triethylgermyl tellurium3. Triorgano tin hydrides cleave the Te — Te bond in diaryl and dialkyl ditellurium compounds forming the organo triorganostannyl tellurium as one of the products (p. 191). 

Because a number of these organometallic compounds are commercially available, they are convenient starting materials for the preparation of certain aliphatic and aromatic diorgano tellurium dihalides. Tetraorgano tin and lead compounds transfer only two of their four organic groups to tellurium. Experiments with dialkyl-diaryl compounds showed that only the aryl groups are transferred. 

The attachment of a C5-side chain by SN2-alkylation at the intended benzylic position with the protected ketoester 139 as the nucleophile proceeded reliably and in good yield to form the alkylated ketoester 140 [86]. The second chain could also be coupled very efficiently by reacting the vinylic bromide 140 in a palladium-catalyzed Stille reaction [106] (review [107]) with the allyl tin compound 141 to afford the dialkylated naphthoquinone 142 (Scheme 36). Halonaphthoquinones have previously been coupled in a palladium/copper-catalyzed reaction by Echavarren et al. [108]. 

Sn-0 Bonded compounds, including the alkoxides R3S11OR 14 and the insoluble dialkyl tin oxides (R2SnO)n, can be used in place of the halides. For example, allyltribu-tyltin, which is a useful reagent in organic synthesis, can be prepared from allylmagne-sium bromide and bis(tributyltin) oxide.15... 

Analogous reactions afford other compounds of the type R3SnR, such as alkyl(tri(cycloalkyl)]tin,408 alkyl(triphenyl)tin,409 alkenyl-(trialkyl)tin and -(tri-aryl)tin,398,410 and alkynyl(triaryl)tin compounds 411 also compounds of the general formula R2SnR 2, such as dialkyl- and diaryl-bis(perfluorovinyl)-tin412 and dialkynyl(diaryl)tin compounds.413... 

Toxicology Exposure is by inhalation and by skin absorption. Certain organic tin compounds (organotins) such as triorganotins are toxic and are used as industrial fungicides and bactericides. All organotin compounds are irritant (eyes, mucous membranes and skin), and toxic. The most toxic ones are trialkyltin compoimds, such as tributyltin oxide, followed by dialkyl and monoalkyltin compounds. In each group, the ethyl derivatives are the most toxic ones. They have maternal toxicities to different extent [76]. 

Dialkyl tin di(alkyl maleates) constitute a popidar class of tin compound that reacts with the polyene sequences that represent colour development, reducing their length and number by undergoing Diels-Alder reactions, and reducing discoloration. 

Mono- and dialkylated or arylated tin salts react in the same way as inorganic tin compounds with catechol violet to form intense blue chelates. Derivatives of tin containing three or four organic groups do not react... 

Procedure. The paper chromatogram or filter paper on which the test solution has been spotted is sprayed with a solution of catechol violet. Mono- or dialkyl or aryl tin compounds are indicated by blue stains. 

The scope of this synthetic method was considerably enlarged when it was found (99) that 1 mole of a mono(iV-phenylformamido)tin compound reacts with 1 mole of a dialkyl- or diaryltin dihydride to give an organoditin monohydride. 

The preparation of tria]kyl(A-phenyl-formamido)tin(IV) compounds of the type 106 from phenylisocyanates is followed by a reduction using dialkyl or diaryltin dihydrides234. 

The structures of some stable stannylenes, such as several amino-, " alkoxy-, and arylthio-substituted intermediates, have been revealed by X-ray crystallography. They are monomeric crystals and the tin atom has the coordination number 2. The divalent tin in such compounds is stabilized by the effects of electronegativity of the ligand atoms and by the donation of the lone-pair electrons to the vacant 5p orbital of the tin. Although the first monomeric dialkyl- and diaryl- stannylenes in... 

Among the group 16 elements, mostly non-metallic ones like TeCl were examined [11]. The reaction with TeCU proceeds in a stepwise manner giving the mono-alkyltellurium and the dialkyl compound in accordance with the stoichiometry of the reagents Eq. (21). As in the case of tin and bismuth, the second alkylation is much slower than the first and the dialkyl species could not be alkylated any further. 

Tin has been detected in rats after oral administration of 10 mg/kg/day tetralkyltin compounds (tetraethyltin, tetrapropyltin, and tetrabutyltin) (Iwai et al. 1982b). The compounds were found in the gastrointestinal tract, kidney and liver, while no retention was observed in brain and blood. The gastrointestinal tract retained primarily tetrapropyltin and tetrabutyltin. Levels (in pg tin/g wet tissue) were highest in the jejunum (5 and 4 pg tin/g, respectively). In the kidney, all 3 tetralkyltin compounds were found and levels ranged from 1 pg tin/g (tetrabutyltin) to less than 4 pg tin/g (tetraethyltin and tetrapropyltin). The liver retained primarily tetrabutyltin (approximately 2pg tin/g). The authors suggestion that the route, rate, and amount of excretion of the tetra- and trialkyltins depend on dialkylation, doses, physical and chemical properties, and route of administration appears reasonable. 

---