Organoceriumreagents, prepared in situ by the treatment of organolithium compounds with cerium(III) iodide, exhibit characteristic reactivities toward ketones; at –65 °C, nucleophilic additions give the corresponding tertiary alcohols in excellent yields, while, at 0 °C to ca. room temperature, reductive coupling and/or reduction of the ketones prevail.
Organoceriumreagents, prepared from organolithiums and anhydrous cerium (III) chloride, react cleanly with easily enolizable ketones to afford the addition products in good to excellent yields.
In the presence of anhydrous cerium(III) chloride, Grignardreagents react with Ketones to afford addition products in high yields, even though the substrates are susceptible to abnormal reactions with Grignardreagents alone.
CeCl3(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 7Li 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 Li3Ln(n-Bu)6(thf)4 increases markedly with decreasing