The lithiation of ferrocene and ruthenocene: A retraction and an improvement

We reported in 1993 an efficient synthesis of ferrocene and ruthenocene mono- and dialdehydes which suggested the first truly specific monolithiation of these two metallocenes (U.T. Mueller Westerhoff, Z. Yang and G. Ingram, J. Organomet. Chem., 463 (1993) 163). Unfortunately, these results were based on inappropriate experimental methods. we have now meticulously analyzed a wide spread of reaction conditions and have concluded that an effective monolithiation of ferrocene and of ruthenocene is possible, but not under the previously described reaction conditions.