An Aminopyridinato Titanium Catalyst for the Intramolecular Hydroaminoalkylation of Secondary Aminoalkenes

The easily accessible 2‐(methylamino)pyridinato titanium complex initially synthesized by Kempe is used as catalyst for efficient intramolecular hydroaminoalkylation reactions of secondary aminoalkenes. The corresponding reactions of N‐aryl‐substituted 1‐aminohept‐6‐enes and 1‐aminohex‐5‐enes directly give access to 2‐methylcyclohexyl‐ or 2‐methylcyclopentylamines in good yields. In addition, intramolecular hydroaminoalkylations of an N‐alkyl‐substituted secondary aminoalkene and a geminally β‐disubstituted substrate are described for the first time. While all products are formed as mixtures of two diastereoisomers, better trans/cis ratios are observed during the formation of 2‐methylcylopentylamines.