Thallium nitrate alkenes

Thallium nitrate— polyethylene glycol Specific for cis and trans alkenes 100... 

Mercuric salts induce oxidative rearrangement of cyclic alkenes and give cycloalkane carboxaldehydes. Cyclohexene, for example, gave cyclopentane carboxaldehyde (404) in 53% yield. Acyclic alkenes such as 2-butene can also be oxidized with mercuric sulfate and sulfuric acid, giving 2-butanone in this case.566 Thallium nitrate [T1(N03)3] is an important reagent for the oxidative rearrangement of cyclic alkenes.567 The reaction is not restricted to carbocyclic compounds, but can also be applied to heterocyclic compounds as shown by the oxidation of 3,4-dihydro-277-pyran (405) to the dimethyl acetal (406) in 65% yield.568... 

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). 

The mechanism of oxidation probably involves in most cases the initial formation of a glycol (15-35) or cyclic ester,and then further oxidation as in 19-7. In line with the electrophilic attack on the alkene, triple-bonds are more resistant to oxidation than double bonds. Terminal triple-bond compounds can be cleaved to carboxylic acids (RC=CHRCOOH) with thallium(III) nitrate or with [bis(trifluoroacetoxy)iodo]pentafluorobenzene, that is, C6F5l(OCOCF3)2, among other reagents. 

A suspension of thallium (III) nitrate in hexane reacts with epoxides to give the corresponding -hydroxy nitrate esters in good yield. The same reagent in acetonitrile has been used to synthesize a-nitratoketones from substituted acetophenones, 1,2-dinitrate esters from alkenes, and 1,3-dinitrates from ring-opening nitration of cyclopropanes. ... 

A suspension of thallium (III) nitrate in pentane at room temperature can react with alkenes to give vtc-dinitrate esters. Cyclohexene reacts with this reagent to give 1,2-cyclohexanediol dinitrate (85 %) (as a mixture of isomers) and 15 % cyclopentanecarboxaldehyde (hydride shift in the dethallation step). Some alkenes react extremely slowly with this reagent e.g. isomeric 5-decenes. 

Heck intramolecular cyclization. Silver carbonate or nitrate was added originally to tandem Heck arylation reactions to depress alkene isomerization, but they also improve selectivity in the -elimination step. Grigg et al.1 have used a number of useful additives such as triethylammonium chloride, sodium formate (15, 248), phenylzinc chloride, as well as silver(l) and thallium(I) salts. In fact, thallium(I) salts... 

Arylthallium bis(trifluoroacetate)s are converted by successive treatment with KF and BF3 into aryl fluorides.Thallium(iii) nitrate (TTN) readily oxidizes dialkyl sulphides and selenides to the corresponding sulphoxides or selenoxides, and 2-(alkylthio)-l-arylethanones (37) into compounds (38) in methanolic solution.In a modification of the TTN oxidative conversion of aryl alkyl ketones into arylacetic acids, enol ethers derived from the ketones are used instead of the ketones themselves. This reduces the formation of side products. Cyclic aralkyl ketones (39) may be ring-expanded and alkylated to give compounds (40) via treatment of their Wittig-derived alkenes with TTN/ an extrapolation of the basic reaction discovered previously. 

Efforts at C-H activation can be divided into three broad categories. The first involves C-H bonds of arenes, heteroarenes and comparable alkenes. In many cases, the formation of the carbon-metal bond may be viewed as an electrophilic substitution reaction (Scheme 3.1), following the same pathway as metallation by main-group metals such as mercury, thallium and lead, as well as classical reactions such as bromination and nitration. This is not, however, always the case. 

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