SRN1 mechanism in bifunctional systems

Alonso, Rubén A.; Rossi, Roberto A.

doi:10.1021/jo01311a041

Cited by 25 publications

(7 citation statements)

References 1 publication

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“…At the time region 0--600 ns, where reactions ( 1)-( 4) and ( 7)-(1 3) are taken into account the rate equations ( 14)-( 17) become eqns. ( 19)- (22). "By single-photon-counting method.…”

Section: Quantitative Analysis Of the E-xperimental Results-(i)mentioning

confidence: 99%

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Photolysis of pyrene and chloropyrene in the presence of triethylamine in acetonitrile: dehalogenation assisted by potassium cyanide

Lemmetyinen¹,

Ovaskainen²,

Nieminen³

et al. 1992

J. Chem. Soc., Perkin Trans. 2

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Kinetics and transient absorption spectra of pyrene-and 1 -chloropyrene-triethylamine (TEA) systems, in the presence and absence of cyanide ions, have been studied b y a nanosecond timeresolved laser flash photolysis method in dry acetonitrile at room temperature. Schemes for c h loropyrene-triet hylami ne-and c h loropyrene-triet hylami ne-CNsystems have been developed and individual rate constants determined either b y direct measurements or by use of computer analysis of the experimental decay curves. The reaction results in the dehalogenation of chloropyrene t o yield pyrene as the reaction product, but high quantum yields (0.2-0.4) are obtained only in the presence of cyanide ions. The hydrogen atoms which replace the chlorines originate from the solvent. This was determined b y deuterium labelling. The reaction proceeds via an exciplex t o radical ions, which recombine to form ion pairs. Cyanide ions attract chlorohydropyrene radicals, which are mainly formed in the reaction between chloropyrene anion radicals and the solvent. The cyanohydropyrenyl radicals formed are in equilibrium with the relatively stable cyanopyrene anion radicals and, b y cleavage of the cyano radicals, yield the reaction product.Paper 1/03584C

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“…At the time region 0--600 ns, where reactions ( 1)-( 4) and ( 7)-(1 3) are taken into account the rate equations ( 14)-( 17) become eqns. ( 19)- (22). "By single-photon-counting method.…”

Section: Quantitative Analysis Of the E-xperimental Results-(i)mentioning

confidence: 99%

“…Kinetic descriptions of the most important parameters obtained by the solution, eqns. ( 19)- (22), are presented in Table 2.…”

Section: Quantitative Analysis Of the E-xperimental Results-(i)mentioning

confidence: 99%

Photolysis of pyrene and chloropyrene in the presence of triethylamine in acetonitrile: dehalogenation assisted by potassium cyanide

Lemmetyinen¹,

Ovaskainen²,

Nieminen³

et al. 1992

J. Chem. Soc., Perkin Trans. 2

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“…Its 1 H NMR spectrum compared very well to the one reported in the literature. [16] Another S RN 1 reaction was carried out as above with 4 (see Scheme 10), and gave 8 as an oil (45% yield) after column chromatography.…”

Section: Scheme 14mentioning

confidence: 99%

A Radical and An Electron Transfer Process Are Compared in Their Regioselectivities Towards A Molecule with Two Different C−I Bonds: Effect of Steric Congestion

et al. 2000

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Steric compression in 1,4-diiodo-2,6-dimethylbenzene (2a) makes the C−I bond flanked by methyls substantially weaker (a buttressing effect) than the unhindered C−I bond. Calculations also confirm the weaker bonding interaction of the hindered C−I bond of 2a. This causes a remarkable regioselectivity toward the weaker bond in dehalogenation by stannyl radicals. Conversely, a much lower regioselectivity is found for a process −a photostimulated S RN 1 reaction with [a] 2663 the enolate ion of a ketone − which requires the conversion of 2a into a radical anion. A calculation of the BDE of the C−I bond for aa ArI •− system is offered. Finally, the hindered aryl radical intermediate resulting from cleavage of the weaker C−I bond of 2a •− shows a modest but detectable discrimination between reduction or substitution, this once again being due to the steric congestion.

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“…[9] In order to circumvent this problem, we carried out an S RN 1 reaction of 2a (0.041 ) with Me 3 CCOCH 2 Ϫ (0.062 ) in DMSO (55 mL, distilled from CaH 2 ) under photostimulation with 16 '350' nm lamps for 20 min. [16] Another S RN 1 reaction was carried out as above with 4 (see Scheme 10), and gave 8 as an oil (45% yield) after column chromatography. The residue of this chromatography was chromatographed once more on silica gel with a toluene/hexane 1:3 eluent and, as a first pure fraction, afforded 15 mg of 7 as an oil.…”

Section: Scheme 14mentioning

confidence: 99%

A Radical and An Electron Transfer Process Are Compared in Their Regioselectivities Towards A Molecule with Two Different C−I Bonds: Effect of Steric Congestion

et al. 2000

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SRN1 mechanism in bifunctional systems

Cited by 25 publications

References 1 publication

Photolysis of pyrene and chloropyrene in the presence of triethylamine in acetonitrile: dehalogenation assisted by potassium cyanide

Photolysis of pyrene and chloropyrene in the presence of triethylamine in acetonitrile: dehalogenation assisted by potassium cyanide

A Radical and An Electron Transfer Process Are Compared in Their Regioselectivities Towards A Molecule with Two Different C−I Bonds: Effect of Steric Congestion

A Radical and An Electron Transfer Process Are Compared in Their Regioselectivities Towards A Molecule with Two Different C−I Bonds: Effect of Steric Congestion

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