Lithium Cyanide Supported by O‐ and N‐Donors

A series of adducts of LiCN, namely Li(Me₂CO₃)CN], Li(Et₂CO₃)CN], and Li(NMP)CN] (NMP = N‐methyl‐2‐pyrrolidone) were prepared by treatment of solvent‐free LiCN with the appropriate donor. The starting material for these approaches, donor‐free LiCN, was quantitatively prepared from Me₃SiCN and LiMe] in diethyl ether at 0 °C. Alternatively, Li(NMP)CN] was synthesized by metathesis reaction of LiCl with NaCN in the presence of stoichiometric amounts of NMP. Although Li(Me₂CO₃)CN] and Li(Et₂CO₃)CN] are water‐sensitive compounds and decompose at the exposure to air, Li(NMP)CN] is stable in air, even at elevated temperatures. The thermal stability of Li(NMP)CN] was proven by differential thermal analysis (DTA). Li(NMP)CN] shows thermal stability up to temperatures of about 132 °C. To evaluate the cyanation ability the reactions of 1‐bromooctane and 3‐bromocyclohexene with unsupported LiCN, Li(NMP)CN], and a mixture of NaCN/LiCl/NMP were investigated. We found that Li(NMP)CN] as well as LiCl/NaCN/NMP are efficient cyanation reagents comparable to the expensive and air‐sensitive, donor‐free LiCN. A product of the chloride‐cyanide‐bromide exchange could be isolated and structurally characterized by X‐ray diffraction.