THE DIPHENYLMAFNESIUM/ALKALI METAL ALKOXIDE SYSTEM. HYDROCARBON-SOLUBLE ORGANOALKALI METAL REAGENTS

Article abstract of DOI:10.1016/0022-328X(85)80143-1

Unsolvated diphenylmagnesium is solubilized in aromatic hydrocarbon solvents by an alkali metal 2-ethoxyethoxide.The mode of interaction between Ph2Mg and MOCH2CH2OEt (M=Li, Na, K) varies with M.For M=Li the complex formed has an Mg/Li ratio equal to 1.3/1.0, and is evidently different from the PhLi/Mg(OCH2CH2OEt) complex.For M=Na the metal-metal interchange apparently leads to a complex identical to thaht derived from PhNa and Mg(OCH2CH2OEt).For M=K the results are not conclusive.The width of the resonance 13C from the ipso-carbon, increases with increasing ionic radius, and for M=K the signal is too broad to be clearly observed .The ipso-carbon in the NMR spectrum of the PhNa/Mg(OCH2CH2OEt) complex has now been shown to give rise to resonance at 175.95 ppm.Metalation experiments involving Ph2Mg along with two equivalents of MOCH2CH2OEt indicated that reactivity increases in the order Li < Na < K.