Photo-Pschorr reaction

Biaryl formation is important when cationic substrates are used, such as diazonium salts (usually in the intramolecular version, the photo-Pschorr reaction [113]) or quaternary ammonium salts [114], In this case PET generates a neutral radical, and this expels nitrogen or an amine molecule yielding an aryl radical. Although the present discussion generally does not include ma-... 

An application of the photo-Pschorr reaction to the 2-aminoiso-quinolines 134 and 175 gave 0-benzylandrocymbine 138 which on debenzylation afforded (+ )-androcymbine (139) (58). The same reaction of diphenolio aminoisoquinoline 176, however, gave the abnormal product, homoproaporphine 93 (58), which would have been formed via the radical intermediates 178, 179, and 180, derived from the diazonium salt (177). 

Ru Many examples of radical arylations by photoredox catalysis have been recently reported [62-64]. For instance, when ArN +X salts are reduced, a C—N bond cleavage occurs to give Nj, an Ar radical, and the anion X . An intramolecular photo-Pschorr reaction is exemplified by the conversion of ArN +X (89) into phenanthrene derivatives 92, in quantitative yields, photocatalyzed by [Ru(bpy)3](BF )j (Scheme 9.12). In this way, the excited state of this ruthenium complex was able to reduce the salt 89 to the corresponding aryl radical 90. This in turn cyclized, thereby... 

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