Nitroxides, deoxygenation

Another methodology is the deoxygenation of nitroxides by (TMSlsSiH, shown in Reaction (22). Indeed, the reaction of this silane with TEMPO, in the presence of thermal or photochemical radical initiators, afforded the corresponding amine in quantitative yield, together with the siloxane (TMS)2Si (H)OTMS. 

Upon irradiation with a Xe lamp (100 W), the typical five-line spectrum characteristic of the nitronyl nitroxide radical 114 (g= 2.0066) was progressively transformed into a seven-line spectrum characteristic of an imino nitroxide radical (Scheme 24). It was proposed that during the irradiation, selective deoxygenation of the radical 114 to the radical 115 had occurred <2003S2145>. 

Nitroxide radical 6 is similar in that it is stable in deoxygenated solution but cannot be isolated as free-radical solid. The n-spin density at the terminal ethynyl carbon atom is estimated from the value of 1.3 G to be 0.05 [5]. 

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