Cation-radical catalyzed Diels-Alder reaction

Electron-transfer catalyzed cycloaddition reactions of unactivated cyclic olefins in weakly coordinating anion electrolyte

“…This process may be triggered by either oneelectron oxidation (Scheme 1) 1 or by photochemical excitation of the olefin. 2 Originally reported by Ledwith 3 , this reaction was developed primarily by Bauld and co-workers, 1,4,5 who extended it to include radical-induced Diels-Alder reactions. 1,5 Compared to strictly thermal reactions of the neutral olefins and diolefins, the rates of both [2 + 2] and [2 + 4] coupling reactions are enormously accelerated by radical cation initiation.…”

Conversion of unsaturated fatty acids - cycloadditions with unsaturated fatty acids [1]

“…The thermal dimerization of cyclohexadiene affords at 200°C after 20 h only 30% of the dimer, whilst via radical cation catalysis at 0°C after 5 min 70% dimer are obtained (eq. 9) [18].…”

Photoinduced electron transfer oxygenations

“…Seemingly, formation of the ultimate products 59-63 could be easily rationalized on the basis of the classical Foote mechanism [84]. However, the proneness of these substrates to undergo an easy singlet oxygen functionalization [31], as well as an exceedingly fast oxygenation of the corresponding (54-58 +-) radical cations, thermally generated by reaction with catalytic amounts of one-electron-oxidizing agents, namely tris(p-bromophenyl) ammoniumyl hexachioroantimonate [146][147][148][149], induced the authors to deeply investigate the actual mechanism operating in these DCA-sensitized reactions.…”