Intramolecular Alkene Hydroamination with Hybrid Catalysts Consisting of a Metal Salt and a Neutral Organic Base

Hybrid catalysts consisting of alkaline earth iodides (AeI 2 ) and the Schwesinger base t Bu P4 catalyse the intramolecular alkene hydroamination of H 2 C=CHCH 2 CR 2 CH 2 NH 2 [CR 2 =CPh 2 , C(CH 2 ) 5 , CMe 2 ]. Activities decrease along the row: Ca > Sr >> Mg > Ba. Hybrid catalysts consisting of t Bu P4 and ZnI 2 , AlI 3 , FeCI 3 or NaI were found to be fully inactive. Also, the hybrid catalyst t Bu P3/CaI 2 was not active which means that the base strength of the non‐nucleophilic organic base must be higher than that of t Bu P3 (p K a BH + = 38.6). Combinations of t Bu P4 with CaX 2 (X = Cl, Br, O i Pr, OTf, NTf 2 ) were found to be fully inactive which may in part be explained by poor solubility. The hybrid catalysis method is therefore limited to the combination t Bu P4/CaI 2 but the iodide ligands may be partially or fully replaced by chiral ligands. Chiral modifications of the hybrid catalysts gave in intramolecular alkene hydroamination ee values up to 33 %.