Dimers hydroxamic esters

In a nonelectrolytic reaction, which is limited to R = primary alkyl, the thio-hydroxamic esters 29 give dimers when irradiated at -64°C in an argon atmosphere ... 

In the presence of the hydrogen donor tri-Af-butyltin hydride, only hydroxamic ester 195 is formed and the reaction is presumed to involve N—O bond homolysis to give the resonance-stabilized Af-alkoxyamidyl radicals (198), which in the presence of BusSnH are reduced to hydroxamic ester according to Scheme 30. In the absence of BusSnH hydride, formation of esters probably involves alkoxyamidyl dimerization to hydrazines (199) as intermediates (see Section Vl.C, Scheme 34), although HERON reactions of 194 with production of methoxynitrene cannot be discounted. Mesityl radicals, formed by the... 

Oxidative dimerization N,N -Diacyl-N,N -dialkoxyhydrazines from hydroxamic acid esters... 

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