The Ullmann Synthesis of Biaryls

Fanta, Paul E.

doi:10.1055/s-1974-23219

Cited by 426 publications

(148 citation statements)

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“…The dinitrile p-NCC 6 F 4 C 6 F 4 CN may be isolated as a by-product of the reaction of sodium iodide with pentafluorobenzonitrile in 5% yield [9]. However we found that it could be conveniently prepared in a one-pot reaction (Recovered yield ca 20%) via an Ullmann coupling reaction [10], of p-BrC 6 F 4 CN using copper-bronze in refluxing DMF (Scheme 1).…”

Section: Resultsmentioning

confidence: 96%

Synthesis and Magnetic Properties of the Novel Dithiadiazolyl Radical, p-NCC6F4C6F4CNSSN

et al. 2004

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Abstract:The dithiadiazolyl radical p-NCC 6 F 4 C 6 F 4 CNSSN• (4) retains its monomeric nature in the solid state with molecules linked together into chains via supramolecular CN···S interactions. Variable temperature magnetic studies on 4 show that it behaves as a near-ideal Curie paramagnet (|θ| less than 0.1 K), indicating negligible intermolecular exchange. The effective magnetic moment (1.78 µ B ) is temperature independent and in excellent agreement with the value expected for an S = ½ paramagnet with g = 2.01 (1.74µ B ). The lack of exchange coupling between radicals is attributed to the absence of significant orbital overlap between radical centres.

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Section: Resultsmentioning

confidence: 96%

Synthesis and Magnetic Properties of the Novel Dithiadiazolyl Radical, p-NCC6F4C6F4CNSSN

et al. 2004

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“…Besides the palladium catalyzed cross coupling reactions such as Sonogashira Hagihara-, [146][148] Suzuki-, [192]- [194] Hartwig Buchwald-, [36][275] [276] Heck- [277] [278] or Stille reactions; [279] these halogen building blocks would also be suitable for Sandmeyer-, [280]- [282] Appel- [283] and even S N Ar-type [178][204] reactions. Furthermore, metal mediated reaction such as Ullmann- [284] and Grignard reaction [285] can be envisaged as well. …”

Section: Figure 57mentioning

confidence: 99%

“…With the introduced electron donating group in compound 104, the Ullmann type coupling [284][296] [311] was performed. The iodinated compound 104 and 8.5 equivalents copper powder were mixed without solvent and slowly heated to 250°C.…”

Section: The Variable Biphenyl Intermediatesmentioning

confidence: 99%

Shape‐Switchable Azo‐Macrocycles

et al. 2009

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The synthesis of four shape‐switchable macrocycles comprising different peripheral substituents is described. The macrocycles 1–4 consist of m‐terphenyl semicircles interlinked by two azo joints. These macrocycles were assembled from nitro‐functionalized m‐terphenyl moieties through reductive dimerization. The semicircles were assembled through Suzuki cross‐coupling reactions. The molecular weights of the macrocycles were determined by vapour pressure osmometry, because mass spectrometry failed in the cases of 2 and 3. The E → Z photoisomerization reactions were analysed by UV/Vis spectroscopy complemented by 1H NMR studies. A very slow thermal back‐reaction indicated considerable stabilization of the Z isomer. The reduced efficiency of the thermal back‐reaction probably arises from the reduced degree of freedom due to the mechanical interlinking of the two azo groups. The photostationary state consisted of all‐Z (85 %) and all‐E isomers (15 %). The E → Z transformation induced by irradiation displayed simple exponential kinetics, which indicates pairwise switching of the two azo groups in a macrocycle, at least on the timescale under investigation. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

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“…The classical Ullmann reaction applies copper bronze as a reducing agent at elevated temperatures. [4][5][6] Later methods used other metals, for example nickel catalyst, generated by coreductants. [7][8][9] Palladium has also been shown to catalyze aryl halide homocoupling under elevated reaction temperatures in the presence of a reducing agent under both transfer [10][11][12] and catalytic hydrogenation conditions.…”

Section: Introductionmentioning

confidence: 99%

Optimization of a catalytic hydrogenation procedure of a prostaglandin intermediate by DOE methods

Rozsumberszki¹,

Horváth²,

Bokotey³

et al. 2004

Arkivoc

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An optimization procedure for the preparation of Beraprost key intermediate 2 is described. The catalytic hydrogenation of lactone 3 was optimized by Design of Experiment (DoE) methods for minimal Ullmann type side product formation. Experiments used a fractional factorial design method followed by a central composite design allowing optimization of a number of factors as well as statistical analysis of results. The response surface analysis showed that the rate of the side reaction, in a defined experimental area, can be described by a second-order polynomial equation in which the water content and the status of the catalyst are the major influences. The results confirm the mechanistic hypothesis of dimer production as a side reaction on the surface of the catalyst.

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The Ullmann Synthesis of Biaryls

Cited by 426 publications

References 0 publications

Synthesis and Magnetic Properties of the Novel Dithiadiazolyl Radical, p-NCC6F4C6F4CNSSN

Synthesis and Magnetic Properties of the Novel Dithiadiazolyl Radical, p-NCC6F4C6F4CNSSN

Shape‐Switchable Azo‐Macrocycles

Optimization of a catalytic hydrogenation procedure of a prostaglandin intermediate by DOE methods

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