Saturated and Aryl Grignard Reagents

Reactions of salinated alkyl halides with saturated alkyl Gngnatd reagents tuc usually relatively slow. 

Similar and more extensive studies have been made of the RLi 4 R Y reaction [77]. For the latter, results support a mechanism analogous to eq. (2.6). A geminate radical pair is formed by transfer of an electron from RLi to R Y these radicals couple and disproportionate in competition wulli diffusion from the cage. Polarized alkyl iodide spectra also result from abstraction of iodine atoms by free alkyl radicals. Metal halogen 

As noted earlier, (he observation of CIDNP indicates that the polarized product is formed in a process involving radical pairs, but does not require that all (or even most) of it is formed by that route. It is possible dial Tmcatalyzed coupling will simple alkyl groups docs not exist, and that 

Mentally mote aeeessible lot reaction as a nucleophile in an S 2 process. 

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