Thallium III acetate

Stereoselective cis-dihydroxylation of the more hindered side of cycloalkenes is achieved with silver(I) or copper(II) acetates and iodine in wet acetic acid (Woodward gly-colization J.B. Siddall, 1966 L. Mangoni, 1973 R. Criegee, 1979) or with thallium(III) acetate via organothallium intermediates (E. Glotter, 1976). In these reactions the intermediate dioxolenium cation is supposed to be opened hydrolytically, not by Sn2 reaction. 

Thallium(III) acetate reacts with alkenes to give 1,2-diol derivatives (see p. 128) while thallium(III) nitrate leads mostly to rearranged carbonyl compounds via organothallium compounds (E.C. Taylor, 1970, 1976 R.J. Ouelette, 1973 W. Rotermund, 1975 R. Criegee, 1979). Very useful reactions in complex syntheses have been those with olefins and ketones (see p. 136) containing conjugated aromatic substituents, e.g. porphyrins (G. W. Kenner, 1973 K.M. Smith, 1975). 

Alkenes can also be oxidized with metallic acetates such as lead tetraacetate or thallium(III) acetate " to give bis-acetates of glycols. Oxidizing agents such as benzoquinone, Mn02, or 02, along with palladium acetate, have been used to convert conjugated dienes to l,4-diacetoxy-2-alkenes (1,4 addition). ... 

Primary (R = H) and secondary aromatic amines react with alkenes in the presence of thallium(III) acetate to give vie- diamines in good yields. " The reaction is not successful for primary aliphatic amines. In another procedure, alkenes can be diaminated by treatment with the osmium compounds R2NOSO2 and R3NOSO (R = t-Bu)," analogous to the osmium compound mentioned at 15-51. The palladium-promoted method of 15-51 has also been extended to diamination. " Alkenes can also be diaminated indirectly by treatment of the aminomercurial compound mentioned in 15-51 with a primary or secondary aromatic amine. 

Vicinal iodo carboxylates may also be prepared from the reaction of olefins either with iodine and potassium iodate in acetic acid/ or with N-iodosuccinimide and a carboxylic acid in chloroform. " A number of new procedures for effecting the hydroxylation or acyloxylation of olefins in a manner similar to the Prevost or Woodward-Prevost reactions include the following iodo acetoxylation with iodine and potassium chlorate in acetic acid followed by acetolysis with potassium acetate reaction with iV-bromoacetamide and silver acetate in acetic acid reaction with thallium(III) acetate in acetic acid and reaction with iodine tris(trifluoroacetate) in pentane. ... 

Thallium(III) acetate Acetic acid, thallium (3+) salt (8,9) (2570-63-0)... 

Monoalkylthallium(III) compounds are unstable (73, 79), and very few examples of this class have been isolated. A number of alkylthallium diacetates have been obtained either from oxythallation of olefins with thallium-(III) acetate (see below) or from exchange reactions such as that shown in Eq. (11) (74, 75). Only four alkylthallium dihalides have been isolated so far, namely a neopentylthallium dihalide (60) [Eq. (12)] and the isomeric 2-, 3-, and 4-pyridiomethylthallium dichlorides (20) [Eq. (13)]. Monoaryl-and monovinylthallium(III) derivatives are considerably more stable than... 

The major problem encountered in the oxidation of olefins by thallium-(III) acetate is the formation of mixtures of products that are frequently... 

The same conclusion was drawn from the results obtained from careful studies of the stereochemistry of the glycol products formed on oxidation of cyclohexene with thallium(III) acetate 3, 83). When dry acetic acid was employed as solvent the product was mainly the tranr-diacetate (XI) in moist acetic acid, however, the mixture of glycol mono- (XII) and diacetates (XIII) which was obtained was mainly cis. These results have been interpreted in terms of initial trans oxythallation, ring inversion. 

Oxidation of the steroidal olefin (XXVII) with thallium(III) acetate gives mainly the allylic acetates (XXXI)-(XXXIII) (Scheme 15), again indicating that trans oxythallation is the preferred reaction course (19). Addition of the electrophile takes place from the less-hindered a-side of the molecule to give the thallinium ion (XXVIII), which by loss of a proton from C-4 would give the alkylthallium diacetate (XXIX). Decomposition of this intermediate by a Type 5 process is probably favorable, as it leads to the resonance-stabilized allylic carbonium ion (XXX), from which the observed products can be derived. Evidence in support of the decomposition process shown in Scheme 15 has been obtained from a study of the exchange reaction between frawr-crotylmercuric acetate and thallium(III) acetate in acetic acid (Scheme 16) (142). 

The reactions of TTN with a variety of unsaturated systems have been studied systematically during the last two years, and the results obtained clearly establish the synthetic utility of the reagent as a specific oxidant. Attempts were made in 1966 by Uemura et al. 162) to oxidize a,)8-unsatur-ated carbonyl compounds with thallium(III) acetate, but were unsuccessful. In 1970, however, Ollis and his co-workers 121-123) reported that prolonged treatment of highly activated chalcones (Scheme 20) with thal-... 

Scheme 20), these acetals could readily be converted into isofiavones. Unfortunately, very low yields of rearrangement products were obtained using thallium(III) acetate, and separation and purification of acetals such as (XXXIV) was extremely tedious. Reaction of chalcones with TTN, on the other hand, is generally complete within a few hours at room temperature 95), and Farkas et al. (J75) have developed the Ollis procedure into a simple method for the preparation of isofiavones (Scheme 21). 

Thallium (TIT) salts of formic, acetic, and trifluoroacetic acids are prepared from the corresponding acid and thallium(III) oxide (11). Other thallium(III) carboxylates can be obtained from the metathesis of thallium(III) acetate and the carboxylic acid (12). They are colorless, hygroscopic solids. 

It is of interest to note that the thallium(III) acetate oxidation of a 2 -hydroxychalcone yields a mixture of a flavone, through participation of the 2 -hydroxy group in the cyclization, and a coumaranone, which presumably arises by further oxidation of an intermediate acetal <70JCS(C)119). 

The iodination of cross-linked polystyrene has been achieved using iodine under strongly acidic reaction conditions [55] or in the presence of thallium(III) acetate [61], but this reaction does not proceed as smoothly as the bromination. More electron-rich arenes, such as thiophenes [45,62-64], furans [46], purines [65], indoles [66], or phenols [67,68] are readily halogenated, even in the presence of oxidant-labile linkers (Figure 6.2). Polystyrene-bound thiophenes have also been iodinated by lithiation with LDA followed by treatment with iodine [64],... 

Manganese(III) acetate, 171 Thallium(III) acetate, 294 Additions involving sulfur... 

Thallium(III) acetate converted 2//-l-benzotellurin at 20° to bis[2-(2 -formyl-cthcnyl)phenyl] ditellurium1. 

The reaction of alkenes with thallium(III) acetate (TTA) forms oxythallium adducts (52) in a similar manner to the case of oxymercuration. The thallium moiety of adducts can be replac by a halogen atom by heating with coppeKI) salts (CuX-KX X = I, Br, Cl) in acetonitrile (equation 24). ° ... 

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