Lead tetra trifluoroacetate

Reaction of steroidal olefins and allylic or homoallylic alcohols with lead tetra(trifluoroacetate) generally gives mixtures of oxidation products. Unsatu-... 

Lead tetraacetate, 71-72,162,278-282,321 Lead tetra(trifluoroacetate), 282-283 Lead thiocyanate, 263 L-Leucyl-L-alanylglycyl-L-valine, 391 Lewis acids, 10... 

Lead tetra(trifluoroacetate), Pb(OCOCF3)4 [1, 564, before Lemieux-Johnson oxidation]. Mol. wt. 659.13, too hygroscopic for m.p. determination. Supplier Peninsular ChemResearch Inc. 

Lead tetraacetate, 32, 76, 77, 95, 130, 131, 233, 234-238, 324, 325, 331, 402 Lead tetraacetate-N-Bromosuccinimide, 238 Lead tetraacetate pyridinate, 237 Lead tetra(trifluoroacetate), 238-239 Leucine, 177... 

Hydroxylation Lead tetra(trifluoroacetate). Osmium tetroxide. Silver acetate-iodine. Silver chlorate. 

Lead tetra(trifluoroacetate) Replacement of hydrogen by hydroxyl... 

Dry lead tetra(trifluoroacetate) added with stirring at room temp, to n-heptane, stirring continued 0.5 hr. and during the following addition of aq. NaOH n-heptanol. Y ca. 45%. - Similarly Benzene phenol. Y ca. 45%. F. e. s. R.E.Partch, Am. Soc. 89, 3662 (1967). 

Methoxy-2-methylnaphthalene, with cobalt trifluoride in trifluoracetic acid upon refluxing for 12 hours afforded in 88% yield the 4,4 -dinaphthyl shown, which was also obtained from oxidation with lead tetra acetate, ferric chloride, thallium(lll) trifluoroacetate and mercuric trifluoroacetate (ref.173). 

Preparation.— Bridgehead positions canying hydrogen in saturated hydrocarbons can be functionalized in high yield by reaction with lead tetra-acetate in methylene chloride-trifluoroacetic acid solution, in the presence of chloride ions, whereas other tertiary positions show low reactivity in this sequence. The bridgehead trifluoroacetates so produced are readily hydrolysed to alcohols (Scheme 1). A hydroxylation process known to be selective for tertiary positions is the reaction... 

Electrochemistry and spectroscopy of the tt cation radical of meso-tetraalkylchlorin (tetra-methyl) and various porphyrins (tetramethyl, tetraethyl, and tetra-ra-propyl) indicate that these do not convert to Nim at low temperatures.280 Optical evidence reveals, however, that oxidation of the tt cation radical of [Ni(pEt2N)(TPP)] leads to a Ni111 cation radical which can be further oxidized to a Ni111 porphyrin dication. Similar studies have been carried out for various other derivatives of me.so-tetraarylporphyrins such as /V-oxides of TPP and 5,10,15,20-tetramesitylpro-phyrin (TMP). Addition of trifluoroacetic acid (TFA) to the /V-oxide of [NinTMP] at —25 °C in CH2C12 results in [Nim(TMP)]+ with a rhombic EPR spectrum, g = 2.40, 2.12, and 2.04.281... 

High yields of amines have also been obtained by reduction of amides with an excess of magnesium aluminum hydride (yield 100%) [577], with lithium trimethoxyaluminohydride at 25° (yield 83%) [94] with sodium bis(2-methoxy-ethoxy)aluminum hydride at 80° (yield 84.5%) [544], with alane in tetra-hydrofuran at 0-25° (isolated yields 46-93%) [994, 1117], with sodium boro-hydride and triethoxyoxonium fluoroborates at room temperature (yields 81-94%) [1121], with sodium borohydride in the presence of acetic or trifluoroacetic acid on refluxing (yields 20-92.5%) [1118], with borane in tetrahydrofuran on refluxing (isolated yields 79-84%) [1119], with borane-dimethyl sulflde complex (5 mol) in tetrahydrofuran on refluxing (isolated yields 37-89%) [1064], and by electrolysis in dilute sulfuric acid at 5° using a lead cathode (yields 63-76%) [1120]. 

Although H NMR spectra of aryllead triacetates can be recorded in CDCI3 solution in the presence of tetra-methylsilane, cleavage of the methyl-silicon bond takes place when tetramethylsilane is treated with an aryllead(rv) tricarboxylate in trifluoroacetic acid.164 When the aryl moiety is substituted with an electron-withdrawing group, quantitative conversion of TMS was observed to give aryl(methyl)lead dicarboxylates 111, (Equation (136)) that were even isolated in two instances, although in modest to moderate yields 55% yield for the 4-fluorophenyl compound and 23% yield for the 4-trifluoroacetamidophenyl compound. 

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