FREE-RADICALS FROM CYCLIC ENONES - AN ELECTRON-PARAMAGNETIC-RESONANCEINVESTIGATION - PART II - RADICAL ADDITIONS

The addition of silyl and germyl radicals to a series of substituted c yclopentenones and cyclohexenones has been investigated using EPR spec troscopy. At low temperatures the 3-position is the preferred site for addition unless it is substituted or sterically hindered in which cas e addition occurs at the carbonyl oxygen. The latter process is also f avoured at higher temperatures but no evidence has been obtained for e ither addition at the 2-position or for an intramolecular migration fo llowing initial attack at the 3- or 2-position.