Single-Electron Transfer and Radical Reactions

Electrophilic metal ions, notably Hg +, can cleave an M-alkyl bond. Two main pathways are seen (i) attack at the a carbon of the alkyl with inversion at carbon (Eq. 8.36) and (ii) attack at the metal or at the M-C bond with retention (Eq. 8.37). The difference has been ascribed to the greater basicity of the metal in the CpFe case. The unpredictable stereochemistry again makes the reaction less useful. 

It is often difficult to differentiate between a true electrophilic abstraction or addition, a one-step process in which a pair of electrons is implicated (Eq. 8.36 and Eq. 37), from a two-step process involving 

Radical abstraction from a ligand is also possible. For example, in Eq. 8.40, an alkyl radical abstracts a hydrogen atom from a coordinated water. In fact, the process is better seen as a concerted transfer from the water and an e transfer from the Ti(III) center. 

Jacques, J. R Tranchier, F. Rose-Munch, E. Rose, G. R. Stephenson, and C. Guyard-Duhayon, Organometallics, 23,184,2004. 

X Barluenga, K. Muniz, M. Tomas, A. Ballesteros, and S. Garcia-Granda, Organometallics, 22,1756,2003. 

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