The first examples of titanium‐catalyzed hydroaminoalkylation reactions of ethylene with secondary amines are presented. The reactions can be achieved with various titanium catalysts and they do not require the use of high pressure equipment. In addition, the first solid‐state structure of a titanapyrrolidine that is formed by insertion of an alkene into the Ti−C bond of a titanaaziridine is reported.

The N−H and C−H bond activation reactions at ambient conditions of seven different secondary allyl amines (Aa−g) with bis(η 5 :η 1 -pentafulvene)titanium complexes (1) h a v e b e e n i n v e s t i g a t e d . B i s ( η 5 : η 1adamantylidenepentafulvene)titanium (1a) reacts with Nallylaniline (Aa), N-allylbenzylamine (Ac), N-allyl-tert-butylamine (Ad), N-allylcyclohexylamine (Ae), and N-allyl-2methylaniline (Af) to give the 1-azabutadiene complexes 2a,c−f with high yields. They are the first complexes of the CH 2 -terminated monoazadiene RNCHCHCH 2 . Using bis(η 5 :η 1 -di-p-tolylpentafulvene)titanium (1b), which exhibits a less Brønsted basic C exo center, and Aa, the β-C−H bond activation can be slowed down so much that the agostic interaction between the titanium center and the C−H bond is detectable via NMR measurements at room temperature. In the reactions of the titanium azabutadiene complexes 2a,b and 3a with carbon monoxide a ligand exchange is observed, forming the titanocene dicarbonyls 4a,b.

The ring enlargement reactions at ambient temperatures of non C-terminus substituted monoazabutadiene (η -RN=CHCH=CH ) titanium complexes 2 are investigated. The insertion of aldehydes/ketones (five examples) and nitriles (four examples) into the Ti-C bonds result in expansion of the five-membered rings to uncommon seven-membered titanacycles 3 and 4 in good yields. These new compounds are fully characterized by NMR spectroscopy and single-crystal X-ray diffraction. In subsequent reactions, the seven-membered ring systems are protolyzed and the released organic fragments are isolated. Whereas the aldehyde/ketone insertion products 3 form substituted δ-amino alcohols 5 after reduction with NaBH CN, the nitrile insertion products 4 form substituted pyrroles 6 via cyclization.

Industrially important ethylene easily inserts into the titanium carbon bond of titanaaziridines to give titanapyrrolidines. Based on this reaction, this work reports the first examples of titanium‐catalyzed hydroaminoalkylation reactions of ethylene with secondary amines, which directly deliver α‐ethylated amines. The picture, created by Iris Töben, shows a simplified catalytic cycle in front of Oldenburg Palace, which is located in the city center of Oldenburg where the researchers developed the new reaction. More information can be found in the Communication by R. Beckhaus, S. Doye, et al. on page 2138.