Thallium triacetate

Several derivatives of indolo[3,2-fi]carbazole, such as the system 185, have been claimed to arise from the reaction of suitably substituted simple indoles on treatment with thallium triacetate in acetic acid. A compound having the purported structure of 185 was thus isolated when 2,3-dimethylindole was used as the substrate [78UC(B)422]. Many years later, it was demonstrated that this product is in fact a derivative of indolo[2,3-c]carbazole (cf. Section VI) (99T12595). 

Although it had been claimed previously that thallium triacetate oxidation of... 

Ethylbenzene, Thallium triacetate Ucmura, S. et al., Bull. Chem. Soc., Japan., 1971, 44, 2571 Application of a published method of thallation to ethylbenzene caused a violent explosion. A reaction mixture of thallium triacetate, acetic acid, perchloric acid and ethylbenzene was stirred at 65°C for 5 h, then filtered from thallous salts. Vacuum evaporation of the filtrate at 60°C gave a pasty residue which exploded. This preparation of ethylphenylthallic acetate perchlorate monohydrate had been done twice previously and uneventfully, as had been analogous preparations involving thallation of benzene, toluene, three isomeric xylenes and anisole in a total of 150 runs, where excessive evaporation had been avoided. 

See Perchloric acid Ethylbenzene, Thallium triacetate See related METAL PERCHLORATES... 

Thallium Triacetate. Pasty residue from evaporation of mixture of thallium triacetate, acetic acid, perchloric acid, and ethyl benzene exploded.16... 

Oxidation of enamines derived from cyclic and acyclic ketones with thallium triacetate in equivalent amount leads to the formation of the corresponding 2-acetoxy ketones75 (Scheme 52). The reactions are stereoselective (the antiparallel attack of the oxidizing agent is preferred over a parallel attack on 3- and 4-/-butylcyclohexanone enamines) and the attack occurs preferentially at the tetrasubstituted enamine double bond, when there is more than one possibility due to isomerism. 

In fact, treatment of cycloalkanone enamines with thallium triacetate, followed by rapid treatment with sodium hydroxide afforded /r[Pg.947]

Enamines are readily available ketone derivatives." Exposure of these compounds to certain transition metal salts has been shown to produce a-oxygenated imines which are rapidly hydrolyzed to their ketone counterparts. Thus, for example, morpholino enamines, prepared in situ, are a-acetoxylated on treatment with thallium triacetate. The process is thought to involve either direct nucleophilic extraction of an acetate unit or the intermediacy of an organothallium species which subsequendy undergoes anchimerically assisted intramolecular acetoxy migration to generate the a-acetoxyimine (Scheme IS). 

Direct treatment of a free acid with thallium triacetate provides the a-acetoxy adds via intramolecular reductive reanangement of the derived thallium enolate. Only simple adds have been used and the necessity to use a large excess of the substrate acid limits the syndetic usefiilness of the procedure. 

Alkenes were reacted with thallium triacetate and azidotrimethylsilane to give 0-azidoalkyl thallium compounds, which were converted in situ to aziridinylazothallium compounds70,71. Only in the case of norbornene derivatives were the initial adducts (cxo.cw-azido-thallium compounds) isolated72. The aziridinylazothallium compound derived from cyclohexene 1 underwent thermal decomposition to give the trans-1,2-diazide, 2 in low yield. However, on treatment with acyl halides or trifluoroacetic anhydride, compound 1 afforded the corresponding 0-halo or 0-trifluoroacetoxy azides70. 

Oxidathedetuageefeyek openes. 1,3,3-Trimethylcyclopropene (1) is converted into l,l-diacetoxy-2,3-dimethy 1-2-butene (2) by oxidation with mercuric acetate in methylene chloride at room temperature. Reaction of (1) with thallium triacetate or... 

Thallium triacetate, TI(0C0CH3)3 1.5H20 (mp 182 C), like the monoacetate, is used for the stereoselective acetoxylation of alkenes [411] and for oxidations of alkenes to epoxides [412]. 

Other oxidants used for epoxidation are dimethyldioxirane [210], ozone [107], thallium triacetate [412], chromic oxide [564], chromyl compounds [679], sodium hypochlorite [112, 689], calcium hypochlorite [704], N-bromosuccinimide in water [746], iodine and silver oxide [751], iodine triacetate [785], electrolysis [119], and microorganisms [1055, 1063]. 

The oxidation of isobutylene with thallium triacetate gives 82% of isobutylene oxide [412]. The oxidation of 1-pentene with peroxytrifluo-roacetic acid yields 81% of propyloxirane [283]. The electrooxidation of... 

Acyl esters of vicinal diols are obtained by the reaction of alkenes with metal carboxylates [436]. Lead tetraacetate in acetic acid at 70 °C converts 1,2-dihydronaphthalene to rranj-l,2-diacetoxy-l,2,3,4-tetrahy-dronaphthalene in 72% yield [436]. The reaction is not always stereospecific. Cyclohexene treated with thallium triacetate gives a mixture of diastereomers in varying ratios, depending on reaction conditions, and byproducts as a result of rearrangements (equation 89) [411],... 

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