CeCl(3)/n‐BuLi: Unraveling Imamoto's Organocerium Reagent

CeCl(3)(thf) reacts at low temperatures with MeLi, t‐BuLi, and n‐BuLi to isolable organocerium complexes. Solvent‐dependent extensive n‐BuLi dissociation is revealed by (7)Li NMR spectroscopy, suggesting “Ce(n‐Bu)(3)(thf)(x)” or solvent‐separated ion pairs like “[Li(thf)(4)][Ce(n‐Bu)(4)(thf)(y)]” as the dominant species of the Imamoto reagent. The stability of complexes Li(3)Ln(n‐Bu)(6)(thf)(4) increases markedly with decreasing Ln(III) size. Closer inspection of the solution behavior of crystalline Li(3)Lu(n‐Bu)(6)(thf)(4) and mixtures of LuCl(3)(thf)(2)/n‐BuLi in THF indicates occurring n‐BuLi dissociation only at molar ratios of <1:3. n‐BuLi‐depleted complex LiLu(n‐Bu)(3)Cl(tmeda)(2) was obtained by treatment of Li(2)Lu(n‐Bu)(5)(tmeda)(2) with ClSiMe(3), at the expense of LiCl incorporation. Imamoto's ketone/tertiary alcohol transformation was examined with 1,3‐diphenylpropan‐2‐one, affording 99 % of alcohol.