Substituted amino radicals sources

We (50) prepared the following tetrazenes in an effort to provide unequivocal sources of the alkenyl-substituted amino radicals. 

Benzotriazoles, when irradiated at a wavelength of 300 nm, have turned out to be convenient sources for the previously unknown 2-amino-substituted aryl radical (Scheme 34) [150]. From a solution of benzotriazole 88 in benzene, 2-aminobiphenyl 89 was isolated in quantitative yield. This elegant approach... 

Thermochemical data for alkyl amino radicals show for alkylhydrazines a trend in D (N-N) for these compounds in which the N-N bond was strengthened by increasing the degree of substitution by methyl in NH2 NH2 . From these values it was possible to determine values for the enthalpies of formation of the alkylamino radicals , and to confirm these by electron impact studies. The latter values were found to be in agreement with those obtained from pyrolysis studies. Hydrazine has often been used as a source of amino radicals by pyrolysis flame decomposition shock tube decomposition , electrodeless discharge and microwave discharge , viz. 

In synthetic contexts, thiyl radicals are known to engage in a number of useful reactions [191-198], including C-H bond abstraction [197, 199-203]. Recently, MacMillan has demonstrated the capacity of catalytically generated thiyl radicals to cleave the C-H bond of benzylic ethers for radical coupling reactions (Fig. 27) to form diaryl methanols (a) [204] or p-amino ethers (b) [205]. The light source is either a Blue LED or a Compact fluorescent lamp (CFL), as designated above. In both reactions, a wide variety of arene components and ether substitutions are tolerated to furnish a diverse set of products and only a catalytic amount of methyl thioglycolate is necessary to affect the desired C-H HAT event. In the formation of diaryl ethers (Fig. 27a), phosphate serves as the base, whereas the P-amino ether... 

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