Titanium‐Catalyzed Intermolecular Hydroaminoalkylation of Allenes and Methylenecyclopropanes.

Intermolecular hydroaminoalkylation reactions of 1,1‐ and 1,3‐disubstituted allenes as well as methylenecyclopropanes with secondary amines can be achieved in the presence of a 2,6‐bis(phenylamino)pyridinato titanium catalyst at 140 °C within 2–8 h. Corresponding reactions of allenes with N‐benzylanilines deliver branched allylamine products in very good yields (up to 83 %) and with branched‐linear‐ratios between 75 : 25 and 95 : 5. In contrast, bicyclic methylenecyclopropanes undergo hydroaminoalkylation with N‐benzylanilines or N‐alkylbenzylamines to give linear products in good to excellent yields (up to 98 %) with perfect regio‐ and diastereoselectivity. The corresponding 1,2,3‐trisubstituted (2‐aminoethyl)cyclopropane products exhibit a structurally interesting cis‐orientation of all three cyclopropane hydrogen atoms. [ABSTRACT FROM AUTHOR]