Electron Transfer in the Reactions of Geminal Dihalides with Ph2P-. Evidence for the Formation of a Carbene Intermediate from a Radical Precursor
作者:E. C. Ashby、Abhay K. Deshpande
DOI:10.1021/jo00127a014
日期:1995.11
The reactions of two sterically hindered geminal dihalides, 6,6-dichloro-5,5-dimethyl-1-hexene (5a) and 6,6-diiodo-5,5-dimethyl-1-hexene (5b), with Ph(2)P(-) have been found to involve a single electron transfer (SET) pathway. Since the corresponding monochloride reacts with Ph(2)P(-) by a S(N)2 pathway, it is clear that adding a second chlorine atom on a carbon atom produces a more favorable reduction potential resulting in a change in mechanism from S(N)2 to SET. Evidence is also presented that shows that the geminal dihalides produce carbene-derived products and that the carbene was derived from a haloalkyl radical precursor.