Synthesis of Heteroleptic Amidinato Calcium Halides via the In‐Situ Grignard Addition Method (iGAM) Complementing the Metalation of Amidines

The in-situ Grignard addition method adds intermediately prepared organo alkaline-earth metal halides onto a suitable substrate. Here, freshly rasped calcium and the carbodiimide R'─N═C═N─R' (R' = SiMe₃, iPr) are suspended in THF at room temperature and then an organyl halide R─X (X = Br, I) is added. Within several hours, intermediately formed R─Ca─X adds onto the carbodiimide yielding the corresponding thf adducts of the amidinato calcium halide {(R'N)₂C─R}CaX. Suitable organyl halides besides aryl iodide are methyl and ethyl halide whereas bulkier isopropyl and tert-butyl iodides give very low yields.