(NHC)NiH‐Catalyzed Intermolecular Regio‐ and Diastereoselective Cross‐Hydroalkenylation of Endocyclic Dienes with α‐Olefins

Highly selective cross‐hydroalkenylations of endocyclic 1,3‐dienes at the least substituted site with α‐olefins were achieved with a set of neutral (NHC)NiIIH(OTf) catalysts and cationic NiII catalysts with a novel NHC ligand. Under heteroatom assistance, skipped dienes were obtained in good yields, often from equal amounts of the two substrates and at a catalyst loading of 2–5 mol %. Rare 4,3‐product selectivity (i.e., with the H atom at C4 and the alkenyl group at C3 of the diene) was observed, which is different from the selectivity of known dimerizations of α‐olefins with both acyclic Co and Fe systems. The influence of the various substituents on the NHC, 1,3‐diene, and α‐olefin on the chemo‐, regio‐, and diastereoselectivity was studied. High levels of chirality transfer were observed with chiral cyclohexadiene derivatives. Heteroatom‐Effekte: 1,4‐Diene mit exo‐Methylengruppen wurden durch Nickel‐katalysierte Kreuzhydroalkenylierungen in hohen Ausbeuten erhalten, sodass endocyclische 1,3‐Diene mit eingebauten Chiralitätszentren nun mit α‐Olefinen kompatibel sind. Sterische Effekte der NHC‐Liganden und Produkte verhindern eine Isomerisierung. DIPP=2,6‐Diisopropylphenyl.