scholarly journals Intramolecular homolytic aromatic substitution of alkyl 2-benzimidazolyl sulfones as a means of entry into alkyl radicals for organic synthesis

2008 ◽  
Vol 49 (18) ◽  
pp. 2999-3003 ◽  
Author(s):  
David Crich ◽  
Daniel Grant
Keyword(s):  
Organic Synthesis ◽  
Aromatic Substitution ◽  
Alkyl Radicals ◽  
Homolytic Aromatic Substitution

scholarly journals Organoboron Mediated Homolytic Aromatic Substitution of N-Methoxypyridinium Salts

2021 ◽  
Author(s):  
Samuel Rieder ◽  
Camilo Meléndez ◽  
Kleni Mulliri ◽  
Philippe Renaud
Keyword(s):  
Rate Constant ◽  
Aromatic Substitution ◽  
Enol Ethers ◽  
Alkyl Radicals ◽  
Homolytic Aromatic Substitution ◽  
Reaction Proceeds ◽  
Order Of Magnitude ◽  
Enol Esters ◽  
The One ◽  
Neutral Conditions

<p>The monoalkylation of N-methoxypyridinium salts with alkyl radicals generated from alkenes (via hydroboration with catecholborane), alkyl iodides (via iodine atom transfer) and xanthates is reported. The reaction proceeds under neutral conditions since no acid is needed to activate the heterocycle and does not require the use of an external oxidant. A rate constant for the addition of a primary radical to N-methoxylepidinium >107 M–1 s–1 was experimentally determined. This rate constant is more than one order of magnitude larger than the one measured for the addition of primary alkyl radical to protonated lepidine demonstrating the remarkable reactivity of methoxypyridinium salts towards radicals. The reaction could be extended to a three component carbopyridinylation of electron rich alkenes including enol esters, enol ethers and enamides.</p>

scholarly journals Organoboron Mediated Homolytic Aromatic Substitution of N-Methoxypyridinium Salts

2021 ◽  
Author(s):  
Samuel Rieder ◽  
Camilo Meléndez ◽  
Kleni Mulliri ◽  
Philippe Renaud
Keyword(s):  
Rate Constant ◽  
Aromatic Substitution ◽  
Enol Ethers ◽  
Alkyl Radicals ◽  
Homolytic Aromatic Substitution ◽  
Reaction Proceeds ◽  
Order Of Magnitude ◽  
Enol Esters ◽  
The One ◽  
Neutral Conditions

<p>The monoalkylation of N-methoxypyridinium salts with alkyl radicals generated from alkenes (via hydroboration with catecholborane), alkyl iodides (via iodine atom transfer) and xanthates is reported. The reaction proceeds under neutral conditions since no acid is needed to activate the heterocycle and does not require the use of an external oxidant. A rate constant for the addition of a primary radical to N-methoxylepidinium >107 M–1 s–1 was experimentally determined. This rate constant is more than one order of magnitude larger than the one measured for the addition of primary alkyl radical to protonated lepidine demonstrating the remarkable reactivity of methoxypyridinium salts towards radicals. The reaction could be extended to a three component carbopyridinylation of electron rich alkenes including enol esters, enol ethers and enamides.</p>

Reversibility of homolytic aromatic substitution: the reaction of p-xylene with phenyl radicals

1974 ◽  
pp. 987 ◽  
Author(s):  
Roberto Henriquez ◽  
Alistair R. Morgan ◽  
Peter Mulholland ◽  
Derek C. Nonhebel ◽  
George G. Smith
Keyword(s):  
Aromatic Substitution ◽  
Phenyl Radicals ◽  
Homolytic Aromatic Substitution
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