Alkyllithium Reagents from Alkyl Halides and Lithium Radical Anions

Article abstract of DOI:10.1021/jo01298a034

The reaction of alkyl halides with three different lithium radical anions, lithium naphthalene (LiN), lithium di-tert-butylnaphthalene (LiDBN), and lithium di-tert-butylbiphenyl (LiDBB), was studied.The reaction of alkyl halides with an excess of LiN, LiDBN, or LiDBB in THF at -78 deg C leads to a consistently high yield (96-100percent) of reduction products (RH, RLi) with a high degree of formation of RLi (anion trapping 93-95percent) in the case of LiDBB.LiDBN consistently produces high yields of reduction products (89-99percent) with widely variable amounts of anion trapping (21-88percent), while LiN provides variable yields of reduction (39-99percent) and anion trapping (24-65percent).Variation of the concentration of lithium bromide and naphthalene and the ratio of alkyl halide to naphthalene in conjunction with the use of deuterium tracer experiments provided evidence consistent with a competition between metalation of the lithium dihydronaphthalenedicarboxylate by alkyllithium and carbonation of alkyllithium in the carbonation step of the analysis.