Fluorination with XeF<sub>2</sub>.<sup>1</sup>44. Effect of Geometry and Heteroatom on the Regioselectivity of Fluorine Introduction into an Aromatic Ring

Zupan, Marko; Iskra, Jernej; Stavber, Stojan

doi:10.1021/jo971496e

Cited by 9 publications

(4 citation statements)

References 46 publications

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“…The results are collected in Tables 2 and 3. Product distribution in the case of fluorination of fluorene with F-TEDA-BF 4 in MeCN as well as with XeF 2 10 is very similar to nitration with fuming HNO 3 in Ac 2 O 11 (Table 2). A much higher proportion of 2-substitution was observed in the case of chlorination 11, 12 with Cl 2 and detritiation in TFA, 11 while bromination with Br 2 proceeded almost regiospecifically to position 2.…”

Section: Resultsmentioning

confidence: 76%

The role of geometry on regioselectivity and rate of fluorination of fluorene and diphenylmethane with Selectfluor™ F-TEDA-BF4

2003

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Diphenylmethane and fluorene were used as target molecules in an investigation of the effect of the geometry of aromatic molecules on the regioselectivity and rate of fluorination with 1-chloromethyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate) (Selectfluor F-TEDA-BF4). In acetonitrile at 80 degrees C ring fluorination of diphenylmethane was accompanied by oxidation of the saturated carbon atom, while in trifluoroacetic acid only ring fluorination with an ortho-para regioselectivity of 1.8:1 was observed. Fluorene was converted in acetonitrile as well as in trifluoroacetic acid into 2- and 4-fluoro substituted products in the relative ratio of 2:1 and 1.2:1, respectively. The reactions in acetonitrile obey a simple rate equation: v = d[F-TEDA]/dt = k2 x [F-TEDA] x [Substrate] and the second order rate constants for the reactions in acetonitrile at 65 degrees C were determined; values of 0.6 x 10(-4) M-1 s-1 for diphenylmethane and 35.5 x 10(-4) M-1 s-1 for fluorene were obtained. The reaction rates for the various functionalisations of fluorene relative to those for diphenylmethane were found to be considerably influenced by the type of functionalisation. Relative rate factors (k(rel) = k2(fluorene)/k2(diphenylmethane)) with values between 59 for fluorination and 712 for chlorination were determined, while the corresponding data for the biphenyl/diphenylmethane pair were only slightly dependent on the type of functionalisation. A reaction pathway involving electron transfer, thus forming cation radical intermediates, was proposed as the main process in the case of fluorination of fluorene with F-TEDA-BF4.

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Section: Resultsmentioning

confidence: 76%

The role of geometry on regioselectivity and rate of fluorination of fluorene and diphenylmethane with Selectfluor™ F-TEDA-BF4

2003

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“…No reaction was observed when NFSI was used as the fluorinating agent. Zupan has also investigated the use of xenon difluoride for the fluorination of dibenzofuran substrates [41]. Addition of xenon difluoride to 33 in dichloromethane at room temperature resulted in a mixture of regioisomeric, fluorinated products 34-36 in a low, combined yield of 17% (Table 2).…”

Section: Scheme 10mentioning

confidence: 99%

Synthesis of fluorinated oxygen- and sulfur-containing heteroaromatics

O’Leary

Jones

O'Donovan

et al. 2015

Journal of Fluorine Chemistry

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“…OEt 2 gives a mixture of the monofluorides 86a,b ± 88a,b. 221 The reaction of XeF 2 with 1-R-2,3,4,5-tetrafluorobenzene (R = H, F, Br, NO 2 ) or 1-R-2,3,4,6-tetrafluorobenzene (R = H, CF 3 ) in HF or CH 2 Cl 2 ± BF 3 . OEt 2 results in the substitution of F for the hydrogen atom in the aromatic ring.…”

Section: Reactions Of Xenon Derivatives With Aromatic and Polyfluoroa...mentioning

confidence: 99%

“…380 The fluorination of thiochroman-4-one (219a) or its 3-bromo derivative (219b) results in thiochromen-4-ones (220a,b), whereas the reaction of 3,3-dibromothiochroman-4-one (219c) gives 3,3dibromo-2-fluorothiochroman-4-one (220c). 378,380 The reaction of thio-4-pyrone with XeF 2 gives dihydro-2,6diphenylthio-4-pyrone (221) which is dehydrogenated by XeF 2 . 378 The reaction of dimethyl sulfide with XeF 2 has been studied in detail.…”

Section: Reactions With Group VI Organoelement Compounds a Reactions ...mentioning

confidence: 99%

Chemistry of xenon derivatives. Synthesis and chemical properties

Brel¹,

Pirkuliev²,

Зефиров³

2001

Russ. Chem. Rev.

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The critical relaxation of the four-state Potts model on L x L lattices with L 5 64 is studied by the Monte Carlo method. The decay of the magnetisation from a nonequilibrium initial state exhibits a crossover from a power-law relaxation for I<< r ' ( L ) to an exponential one for r > > f ' ( L ) ,where t ' ( L ) is some crossover time. This crossover is discussed within the context of dynamic finite-size scaling theory. As a result, the dynamic critical exponent is estimated to be Z = 2.94 * 0.29.

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Fluorination with XeF₂.¹44. Effect of Geometry and Heteroatom on the Regioselectivity of Fluorine Introduction into an Aromatic Ring

Cited by 9 publications

References 46 publications

The role of geometry on regioselectivity and rate of fluorination of fluorene and diphenylmethane with Selectfluor™ F-TEDA-BF4

The role of geometry on regioselectivity and rate of fluorination of fluorene and diphenylmethane with Selectfluor™ F-TEDA-BF4

Synthesis of fluorinated oxygen- and sulfur-containing heteroaromatics

Chemistry of xenon derivatives. Synthesis and chemical properties

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Fluorination with XeF2.144. Effect of Geometry and Heteroatom on the Regioselectivity of Fluorine Introduction into an Aromatic Ring

Cited by 9 publications

References 46 publications

The role of geometry on regioselectivity and rate of fluorination of fluorene and diphenylmethane with Selectfluor™ F-TEDA-BF4

The role of geometry on regioselectivity and rate of fluorination of fluorene and diphenylmethane with Selectfluor™ F-TEDA-BF4

Synthesis of fluorinated oxygen- and sulfur-containing heteroaromatics

Chemistry of xenon derivatives. Synthesis and chemical properties

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Fluorination with XeF₂.¹44. Effect of Geometry and Heteroatom on the Regioselectivity of Fluorine Introduction into an Aromatic Ring