Oxamination Reactions

Electron-transfer/organocatalytic reactions were postulated in oxamination reactions [9] later it was demonstrated [10] that the reaction follows preferentially a polar enamine activation manifold when FeCls was used in DME as oxidizing agent the metal coordinates rapidly to the nitroxyl radical of TEMPO (2,2,6,6-tetramethylpiperidine-l-oxyl) (Scheme 39.2) [llj. SOMO conditions were find by replacing the metal salt by a non-coordinating oxidizer such as tris(p-bromophenyl) aminium hexachloroantimonate [12]. Under these conditions the ET reaction arguably afforded the enamine radical cation, which was trapped by TEMPO, or by styrene as a purported SOMOphile partner. 

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