1164-05-2Relevant articles and documents
Acid catalysis vs. electron-transfer catalysis via organic cations or cation-radicals as the reactive intermediate. Are these distinctive mechanisms?
Rathore, Rajendra,Kochi, Jay K.
, p. 114 - 130 (2007/10/03)
Proton transfer to aromatic and olefinic donors (D) leads to the facile interchange of transient carbocations (DH+) and cation-radical (D+.). The same types of cation and cation-radical are reactive intermediates in the acid catalysis and the electron-transfer catalysis of such organic transformations as benzylic coupling, epoxide/pinacol rearrangements and cis-trans isomerization of stilbenes when they are both carried out under otherwise identical reaction conditions. However, the rapid exchange of diamagnetic cations and paramagnetic cation-radicals blurs the traditional view of separate electrophilic and homolytic processes, and rigorous experimental evidence is required to establish whether acid catalysis and electron-transfer catalysis actually represent distinct mechanistic categories. Acta Chemica Scandinavica 1998.
Radical-Cation Catalysis in the Synthesis of Diphenylmethanes via the Dealkylative Coupling of Benzylic Ethers
Rathore, Rajendra,Kochi, Jay K.
, p. 7479 - 7490 (2007/10/03)
The dealkylative coupling of benzyl alkyl ethers (ArCH2OR) to yield the corresponding diarylmethanes (ArCH2Ar) together with dialkoxymethane (ROCH2OR) is catalyzed by small amounts of 1-electron oxidants (such as aromatic cation radicals, NO(1+), etc.) or by an equivalent electrochemical (anodic) method.The catalytic method is successfully employed for the facile synthesis of a novel macrocyclic crown ether 18 that contains a diarylmethane linkage.On the basis of the spectral observation of the radical cation ArCH2OR.+ and the excellent catalytic efficiency with turnover numbers in excess of 1E2, an electron-transfer and an alternative electrophilic chain mechanism are discussed for the dealkylative coupling process.
