Thallium in organic synthesis. 44. Oxidative rearrangements via oxythallation with thallium(III) nitrate supported on clay

Taylor, Edward C.; Chiang, Chih-Shu; McKillop, Alexander; White, Joseph F.

doi:10.1021/ja00437a082

Cited by 90 publications

(23 citation statements)

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“…Reinvestigating the previously reported 6 reaction of 1-tetralone (1) with TTN/K-10, we observed that the ratio between the products of ring contraction 2 and of aoxidation 3 increased to at least 5:1, using excess (2 eq.) of the oxidant and pentane as solvent (Scheme 1).…”

Section: Resultssupporting

confidence: 62%

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The reaction of 1-tetralones with thallium trinitrate supported on clay: ring contraction vs alpha-oxidation

Ferraz¹,

Silva²,

Aguilar³

et al. 2001

J. Braz. Chem. Soc.

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A reação de uma série de 1-tetralonas com trinitrato de tálio adsorvido em Montmorilonita K-10 forneceu produtos de contração de anel (1-indanocarboxilatos de metila) e/ou a-oxidação (2-metóxi-1-tetralonas), em rendimentos bastante variáveis.The reaction of a series of 1-tetralones with thallium trinitrate supported on Montmorillonite K-10 clay led to products of ring contraction (methyl indan-1-carboxylates) and/or a-oxidation (2-methoxy-1-tetralones), in variable yields.

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Section: Resultssupporting

confidence: 62%

“…Thallium(III) nitrate was purchased from Aldrich and was used as received. TTN.3MeOH/K-10 was prepared by the procedure described by Taylor et al 6 . 1 H and 13 C NMR spectra were recorded on Bruker AC-200, DPX-300 or DRX-500 spectrometer.…”

Section: Methodsmentioning

confidence: 99%

The reaction of 1-tetralones with thallium trinitrate supported on clay: ring contraction vs alpha-oxidation

Ferraz¹,

Silva²,

Aguilar³

et al. 2001

J. Braz. Chem. Soc.

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“…13,14 This facilitates the electron transfer process between CAN and substrates; thus it may cause the deprotection reactions to proceed much faster. [15][16][17] Use of silica gel as support could also increase the effective surface area and constrain both the substrate and the reactant in pores for decreasing the entropy of activation for electron transfer. 13,14 To realize generality of the CAN-silica gel reagent in de-tert-butoxycabonylation, we treated it with the t-BOC containing compounds 1, 3, 5, 7, 9, 11, and 13 in toluene at reflux.…”

Section: Resultsmentioning

confidence: 99%

Ceric ammonium nitrate impregnated on silica gel in the removal of the tert-butoxycarbonyl group

Hwu¹,

Jain²,

Tsai³

et al. 2002

Arkivoc

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The tert-butoxycarbonyl group was efficiently (80-99% yields) removed from an amino, hydroxy, or mercapto functionality in organic compounds by use of 0.20 equiv of Ce(NH 4 ) 2 (NO 3 ) 6 in acetonitrile at reflux. Application of the solid-supported reagent involving the use of 0.20 equiv of Ce(NH 4 ) 2 (NO 3 ) 6 impregnated on silica gel in toluene at reflux gave the deprotected products in 90-99% yields. These reactions likely proceed through an electron transfer process.

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“…Under these conditions, a complex mixture of compounds was formed. 42 The thallium(III)-promoted oxidation of 1-tetralones was then investigated using the conditions previously described by Taylor et al 43 The reaction of a series of 1-tetralones with TTN supported on Montmorillonite K-10 clay led to products of ring contraction and/or α-oxidation, as illustrated by Scheme Singh et al described that the reaction of tetrahydro-4-quinolones with TTN gave the ring-contraction product together with a 3-methoxytetrahydro-4-quinolone as a minor product. A representative example is shown in Scheme 10.…”

Section: Scheme 8 Mechanism For the Thallium(iii)-mediated Ring Contrmentioning

confidence: 99%

Adventures in Ring-Contraction Reactions

Silva

2014

Synlett

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Nearly two decades of work on ring-contraction reactions is discussed in this account. We have developed several reliable protocols for the rearrangement of a number of different substrates using thallium(III) salts and, more recently, hypervalent iodine(III) reagents. A variety of ring systems, such as cyclopentanes, cis-and trans-hydrindanes, and indanes, can be obtained using these methods. Additionally, the stereoselective total syntheses of the sesquiterpenes (±)-, (-)-and (+)-mutisianthol and (+)-bakkenolide A, the indole alkaloid (±)-and (+)-trans-trikentrin A, and the potential drug (±)-indatraline have been achieved through a ring-contraction approach. 1 Introduction 2 Ring-Contraction Reactions Promoted by Thallium(III) 2.1 Thallium(III)-Mediated Ring Contraction of Cyclic Ketones 2.2 Thallium(III)-Mediated Ring Contraction of Cyclic Olefins 2.3 Thallium(III)-Mediated Ring Contraction of Homoallylic Alcohols 3 Ring-Contraction Reactions Promoted by Iodine(III) 4 Conclusion Key words: total synthesis, ring contractions, oxidative rearrangements, thallium(III), hypervalent iodine O TTN (1.1 equiv) CH 2 Cl 2 , r.t., 24 h CO 2 H 87% O TTN (1.5 equiv) CH 2 Cl 2 , r.t., 48 h CO 2 H 65%

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Thallium in organic synthesis. 44. Oxidative rearrangements via oxythallation with thallium(III) nitrate supported on clay

Cited by 90 publications

References 0 publications

The reaction of 1-tetralones with thallium trinitrate supported on clay: ring contraction vs alpha-oxidation

The reaction of 1-tetralones with thallium trinitrate supported on clay: ring contraction vs alpha-oxidation

Ceric ammonium nitrate impregnated on silica gel in the removal of the tert-butoxycarbonyl group

Adventures in Ring-Contraction Reactions

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