Chiral Amido Alkyl Rare Earth Complexes: A New Family of Asymmetric Intramolecular Hydroamination Catalysts

Abstract

New chiral binaphthylamido alkyl ate and neutral yttrium and ytterbium complexes have been synthesized and characterized. X-ray structures have been obtained for ate alkyl complexes [(R)-C20H12(NC5H9)2]Y[(μ-Me)2Li(THF)2(μ-Me)Li(THF)] and [(R)-C20H12(NC5H9)2]Ln[(μ-Me)2Li(TMEDA)(μ-Me)Li(OEt2)] (Ln = Y, Yb) and for the neutral complex [(R)-C20H12(NC5H9)2]YCH2SiMe3(DME). Both types of complexes can be easily prepared in a one-pot procedure starting from yttrium and ytterbium chlorides and used in situ. They proved to be very efficient catalysts for enantioselective intramolecular hydroamination of aminopentenes or aminohexene at room temperature with enantiomeric excesses up to 83%.