Regioselective addition reaction of group IVB organometallic radicals to 2,6-dimethoxybenzoquinone and to some substituted pyrazines: an electron spin resonance study

The results of an ESR study on the spin adducts derived from the reaction between .MR3 organometallic radicals (M = Si, Ge, Sn, Pb) and 2,6-dimethoxybenzoquinone are reported. For the two heavier Group IVB elements two isomeric radical adducts have been detected, whereas only the less hindered isomer could be observed with silicon and germanium centred radicals. Thje results of a similar investigation on the adducts with pyrazine and some of its derivatives are also reported.