Organocerium chemistry

[4] Some of the best characterized organocerium(IV) compounds feature cyclopentadienyl ligands, e.g. Ce(C5H5)3Cl[5] As reagents in organic chemistry, organocerium compounds are typically prepared in situ by treatment of cerium trichloride with organolithium or Grignard reagent.

Precomplexation with tetrahydrofuran is important for the success of the transmetallation, with most procedures involving "vigorous stirring for a period of no less than 2 hours".

[10] This preference for direct addition is attributed to the oxophilicity of the cerium reagent, which activates the carbonyl for nucleophilic attack.

[2] Despite this high reactivity, organocerium reagents are almost entirely non-basic, tolerating the presence of free alcohols and amines as well as enolizable α-protons.

Shown below is a key coupling step in the total synthesis of roseophilin, a potent antitumor antibiotic.

structure of (C 5 (CH 3 ) 4 H) 3 Ce . Color code: green = Ce, gray = C, white = H.
structure of Ce(CH 3 ) 6 [Li(tmeda)] 3 , where tmeda is (CH 3 ) 2 NCH 2 CH 2 N(CH 3 ) 2
Examples of various organocerium reagents previously reported.
Examples of various organocerium reagents previously reported.
Nucleophilicity of organocerium reagents
Nucleophilicity of organocerium reagents
Non-basic tendencies in organocerium reagents
Non-basic tendencies in organocerium reagents
Reactivity and selectivity of organocerium compounds
Reactivity and selectivity of organocerium compounds
Total synthesis of roseophilin using an organocerium reagent
Total synthesis of roseophilin using an organocerium reagent