Anti-Markovnikov Hydroamination of Aromatic Alkenes with Secondary Amines Catalyzed by Easily Accessible Yttrium Complexes

摘要

Binaphthylamido alkyl yttrium complexes have been proven to promote the anti-Markovnikov addition between various styrene derivatives and secondary amines efficiently. Although the reaction has to be performed at high temperature, it is realized advantageously with a 1:2 amine/alkene molar ratio to deliver the hydroamination product in a satisfactory isolated yield. Furthermore, the reaction with 2-vinylpyridine proceeds at room temperature within a few minutes with a low catalyst loading of 1 mol %. The procedure has been extended to a tandem intermolecular anti-Markovnikov-intramolecular Markovnikov hydroamination for which the chiral precatalyst delivered the targeted product in up to 85% yield and 48% enantiomeric excess.