The effect of nitro groups on oxidative cyclisation of chalcones by thallium(III) nitrate(TTN)

2′-Hydroxy-3′-nitrochalcones on oxidation with thallium(III) nitrate do not give rearranged intermediates that can give isoflavones, instead cyclisation gives benzyl-idenebenzofuran-3(2H)-one derivatives.     

Reaction of grayanotoxin-II with thallium (III) nitrate

Reaction of grayanotoxin-II (1) with thallium nitrate gave 3(S), 20-epoxy-6 (S), 14 (R), 16 (R)-trihydroxy-5-oxo-5, 10-seco-ent-kaur-1 (10) -ene (2). The structure of 2 was elucidated by the X-ray diffraction analysis of its reduction product (3).     

The Oxidation of Some Aryldialkylamines with Thallium (III) Nitrate (TTN) in Various Solvents

The oxidation of organic substrates with thallium (III) nitrate (TTN) has been summarised in a recent review¹. No systematic study is available using aromatic tertiary amines as substrates. We showed in two previous reports^2,3 that these compounds undergo oxidative dealkylation and nitration when oxidised with cerium (IV) ammonium nitrate (CAN).     

Stereoselective synthesis of cyclic ethers via bromine assistedepoxide ring expansion

9-Oxabicyclo[6.1.O]non-4-ene reacts with bromine to give stereoselectively trans, trans-2,6-dibromo-9-oxabicyclo[3.3.1]nonane and trans, trans-2,5-dibromo-9-oxabicyclo[4.2.1]nonane.     

Oxidation of 4-chromanones with thallium(III) nitrate

Treatment of 4-chromanones 1a-g with thallium(III) nitrate in acidic methanol results mainly in dehydrogenation, whereas α-methoxylation and/or Taylor-McKillop rearrangement predominate in trimethyl orthoformate. The mechanistic features of these oxidations are briefly discussed.     

Regioselective indium(III) trifluoromethanesulfonate-catalyzed hydrothiolation of non-activated olefins

Indium(III) trifluoromethanesulfonate was found to be an excellent catalyst for the highly regioselective intra- and intermolecular addition of thiols to non-activated olefins and could be recycled and reused without loss of activity.     

C-H activation in bithiazole ring with thallium(III) ion

Two novel organometallic complex of 2,2′-dimethyl-4,4′-bithiazole (dm4bt) ligand (L) with formula [Tl(dm4bt)₂(NO₃)(H₂O)] (1) and [Tl(dm4bt)₂(NO₃)(DMSO)] (2) have been synthesized and structurally characterized by elemental analysis, FT-IR, ¹H NMR spectra and X-ray crystallography. These complexes also display the first transoid conformation in bithiazole ligands in which C-H bond activation in bithiazole ring is observed with Tl(III) ion.     

Oxidation of trans-alloocimene by thallium(III) nitrate

We have obtained 2,7-dimethoxy-2,7-dimethyl-3,5-octadiene by the action of thallium(III) nitrate on trans-allo-ocimene.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1087–1089, May, 1990.     

Carbenoid type base induced ring expansion of the adducts of cyclic ketones with bis(phenylthio)methyllithium

In another application of the principle that metallo derivatives of bis(phenylthio)acetals behave as carbenoids when present in the same molecule with another anionic group, the adducts of cyclic ketones with bis(phenylthio)methyllithium react with an alkyllithium to yield the ring expanded α-(phenylthio) ketones.     

Regiochemical studies of the ring expansion reactions of hydroxy azides with cyclic ketones

The regiochemistry of ring expansions of 2-substituted cyclic ketones using 1,2-azidoethanol and 1,3-azidopropanol was examined. It was determined that the reactions of ketones with an adjacent methyl or ethyl group are generally unselective, but that bulkier substituents lead to preferential migration of the more highly substituted carbon. In addition, it was found that ketones bearing inductively electron-withdrawing substituents (OMe, Ph, Br) undergo selective migration of the less highly substituted carbon. For some substrates, alternative reaction pathways were also identified.     

Thallium(II) in the chemically induced thallium(I)-Thallium(III) exchange

The rate of the electron exchange between thallium(I) and thallium(III) induced by iron(II) has been measured at various concentrations of Tl(I), Tl(III), and Fe(II).²⁰⁴Tl tracer, initially in the Tl(I) state, was used. Exchange induced by the separation method was less than 0.01%. The mechanism earlier discussed is $$\begin{gathered} Tl^{III} + Fe^{II} \rightleftharpoons Tl^{II} + Fe^{III} \left( {k_1 ,k_{ - 1} } \right) \hfill \\ Tl^{II} + Fe^{II} \rightharpoonup Tl^I + Fe^{III} \left( {k_2 } \right) \hfill \\ *Tl^I + Tl^{II} \rightleftharpoons *Tl^{II} + Tl^I \left( {k_I } \right) \hfill \\ *Tl^{II} + Tl^{III} \rightleftharpoons *Tl^{III} + Tl^{II} \left( {k_{III} } \right), \hfill \\ \end{gathered} $$ which provides an exchange path in addition to the two-electron reaction^*Tl^I+Tl^III?^*Tl^III+Tl^I (k_ex). The rate law deduced from this mechanism agrees with experiment over a limited range of conditions but fails to account for the observed effect at low concentrations of Tl(I). The additional rate can be represented by inclusion of a term in which the rate of the induced exchange is independent of the concentration of Tl(I). When treated according to the resulting complete rate law the data are consistent with earlier photochemical studies. The present results in combination with other data give k₂=3·10⁶ M^?1·sec^?1 in 1M perchloric acid at 25°C. This is in satisfactory agreement with a recent pulse radiolysis measurement as well as with independent flash photolysis studies.     

Regioselective hydrophenylation of olefins catalyzed by an Ir(III) complex

The novel, anti-Markovnikov, arylation of olefins with benzene to produce straight-chain alkylbenzenes with higher selectivity than branched alkylbenzenes is catalyzed by [Ir(μ-acac-O,O′,C³)(acac-O,O′)(acac-C³)]₂ (acac=acetylacetonato), 1 [J. Am. Chem. Soc. 122 (2000) 7414]. The reaction of benzene with propylene gave n-propylbenzene and cumene in 61 and 39% selectivities, respectively. The reaction of benzene and styrene afforded 1,2-diphenylethane in 98% selectivity. Considering the anti-Markovnikov regioselectivity and lack of inhibition by water, we propose that the reaction does not proceed via a Friedel–Crafts, carbocation, mechanism. Complex 1, amongst the various transition metal complexes examined, is the most efficient for catalyzing the anti-Markovnikov olefin arylation. The crystal structure of complex 1 was solved and is consistent with a binuclear Ir(III) structure with three different types of coordinated acac ligands as reported by earlier solution IR and NMR analyses. [Ir(μ-acac-O,O′,C³)(acac-O,O′)Cl]₂, 2, was prepared by the reaction of complex 1 with benzoyl chloride, and the crystal structure was also reported.     

Rapid Regeneration of Carbonyl Compounds from Tosylhydrazones with Thallium Trinitrate(TTN)

Tosylhydrazones can be rapidly converted into corresponding carbonyl compounds in good to excellent yields with thallium trinitrate (TTN) under mild conditions.     

Oxidation of vanillins with thallium(III) nitrate. An exercise in NMR spectroscopy and photochemistry

Oxidation of isovanillin, vanillin and o-vanillin with TI(NO₃)₃ in MeOH gave the dimethyl acetals of 6,6-dimethoxy-2,4-cyclohexadien-1-one aldehydes (4–6 which dimerized spontaneously to give a single product each (7–9) the structure of which was elucidated by ¹H and ¹³C NMR, photocyclization to the cage compounds 12–14 and of 7 and 9 by X-ray diffraction as well.     

Reaction of thallium(III) salts with homoallylic alcohols: ring contraction vs. dimethoxylation

The oxidation of 2-(3,4-dihydronaphthalen-1-yl)-ethanol (1) with a variety of thallium(III) salts was investigated. An indan, formed by a ring contraction reaction, was obtained in good to moderate yields under a variety of reaction conditions: i) thallium triacetate (TTA) in aqueous AcOH; ii) thallium tris-trifluoroacetate (TTFA) in aqueous TFA; iii) TTFA in CH(2)Cl(2); iv) thallium tripropionate (TTP) in aqueous propionic acid and v) thallium tris-[(S)-(-)-triacetoxypropionate] in aqueous (S)-(-)-2-acetoxypropionic acid. On the other hand, the reaction of compound 1 with TTA in methanol led to a 2:1 mixture of the corresponding cis- and trans-dimethoxylated compounds, respectively.These compounds were formed by a thallium-promoted addition of methanol to the double bond.     

Rhodium(III) catalyzed oxidation of cyclic ketones by alkaline hexacyanoferrate(III)

The kinetics of the oxidation of 2-methyl cyclohexanone and cycloheptanone with Fe(CN)₆ ³⁻ catalyzed by RhCl₃ in alkaline medium was investigated at four temperatures. The rate follows direct proportionality with respect to lower concentrations of hexacyanoferrate(III) ion, but tends to become zero order at higher concentrations of the oxidant, while the reaction shows first-order kinetics with respect to hydroxide ion and cyclic ketone concentrations. The rate shows a peculiar nature with respect to RhCl₃ concentrations in that it increases with increase in catalyst at low catalyst concentrations but after reaching a maximum, further increase in concentration retards the rate. An increase in the ionic strength of the medium increases the rate, while increase in the Fe(CN)₆ ⁴⁻ concentration decreases the rate.     

铑(Ⅲ)催化N-磺酰基2-甲酰苯胺与烯烃环化制备(2H)喹啉(英文)

开发了一种用铑(III)催化的N-磺酰基2-氨基苯甲醛与烯烃环化生成喹啉衍生物的方法,得到较高产率的喹啉衍生物,并且在反应条件下,反应具有较好的官能团兼容性.这是首次运用铑(III)作为催化剂合成烷基1-磺酰基-1,2-二氢喹啉-3-羧酸酯.该催化体系表现较好的催化性且反应操作较为简单.