Single Electron Transfer in Nucleophilic Aliphatic Substitution. Evidence for Single Electron Transfer in the Reactions of 1-Halonorbornanes with Various Nucleophiles

Article abstract of DOI:10.1021/jo00085a012

A series of 1-halonorbornanes was used as a model system in reactions with several nucleophiles in order to determine the involvement of single electron transfer (SET) in nucleophilic aliphatic substitution in the absence of light.The 1-halonorbornanes were allowed to react with Me3Sn(1-), Ph2P(1-), AlH4(1-), N(iPr)2(1-), SPh(1-), and the 2-nitropropyl anion in the ether solvents at room temperature to 0 deg C.The results of product analyses, the use of radical and radical anion trapping reagents, the results of deuterium labeling studies, and the nucleofugality effect support a SET mechanism for the reactions involving 1-iodonorbornane.Convincing evidence that reduction of hindered alkyl iodides with LiAlH4 takes place by a SET pathway rather than by an impurity-initiated halogen atom radical chain process followed by an S_N2 pathway, is presented.