Imine ligands carbene insertion

To date, the most frequently used ligand for combinatorial approaches to catalyst development have been imine-type ligands. From a synthetic point of view this is logical, since imines are readily accessible from the reaction of aldehydes with primary or secondary amines. Since there are large numbers of aldehydes and amines that are commercially available the synthesis of a variety of imine ligands with different electronic and steric properties is easily achieved. Additionally, catalysts based on imine ligands are useful in a number of different catalytic processes. Libraries of imine ligands have been used in catalysts of the Strecker reaction, the aza-Diels-Alder reaction, diethylzinc addition, epoxidation, carbene insertions, and alkene polymerizations. 

Cationic carbyne complexes, such as [(CO)5CrsCNEt2] and [Cp(CO)2M =C-Aryl]+ (M = Mn, Re), were shown to readily add neutral and anionic nucleophiles to the carbyne carbon atom to give the corresponding cationic or neutral carbene complexes. Carbene complexes have also been obtained in the reaction of [Cp(CO)2Mn = C-Tol]+ with Ph(H)C=NMe and Ph(H)C=N-N=C(H)Ph [6]. The products result from insertion of the imine between the carbyne carbon and a carbon of the Cp ligand. We now report on the reactions of [Cp(CO)2Mn = C-Ph] + and substituted derivatives thereof with electron-rich NsC and C = C compounds. The aim of our investigations was to study the possibility of transferring the carbyne ligand to these multiple bonds. 

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