Reaction of Chiral Secondary Amines with [(畏5-C5Me5)MCl2]2 (M = Rh(III), Ir(III)): Cyclometalation with or without Dehydrogenation

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• 作者：Laurent Barloy ; Jean-Thomas Issenhuth ; Marisa G. Weaver ; Nicolas Pannetier ; Claude Sirlin ; Michel Pfeffer
• 刊名：Organometallics
• 出版年：2011
• 出版时间：March 14, 2011
• 年：2011
• 卷：30
• 期：5
• 页码：1168-1174
• 全文大小：844K
• 年卷期：v.30,no.5(March 14, 2011)
• ISSN：1520-6041

文摘

The reaction of (2R,5R)-2,5-diphenylpyrrolidine (L¹) with [(畏⁵-C₅Me₅)MCl₂]₂ (M = Rh, Ir) in acetonitrile in the presence of KPF₆ and NaOH at room temperature led to mixtures of two products, [(畏⁵-C₅Me₅)M(N鈭扖)(NCMe)](PF₆) (N鈭扖 designating a cyclometalated ligand). These products were cyclometalated complexes of pyrrolidine ((R_C,R_C,R_N,R_M)-1 (M = Ir) or (R_C,R_C,R_N,R_M)-2 (M = Rh)) and of pyrroline ((R_C,S_M)-3 (M = Ir) or (R_C,S_M)-4 (M = Rh)), respectively. With M = Ir, when the reaction was performed in open air, the only product observed was the cyclometalated imine derivative (R_C)-3. The genuine pyrroline complexes were prepared as the racemic compounds (卤)-3, (卤)-4, and (卤)-4鈥?/b> in good yields by cyclometalating (卤)-2,5-diphenylpyrroline (L²) with [(畏⁵-C₅Me₅)MCl₂]₂. These latter compounds were fully characterized; the crystal structures of (R_C)-3 and (卤)-4鈥?/b> were similar and revealed that the C鈺怤 units were endo to the metallacyclic ring. The reaction in acetonitrile of (R,R)-bis(1-phenylethyl)amine (L³) with [(畏⁵-C₅Me₅)MCl₂]₂ (M = Rh, Ir) in the presence of KPF₆ and NaOH at room temperature led to mixtures, within which the cyclometalated dehydrogenated imine cations [(畏⁵-C₅Me₅)M(C₆H₄-2-CMe鈺怤CHMePh)]⁺ were identified by electrospray mass spectroscopy. The corresponding iridium complex was obtained pure and fully characterized as (R_C)-5 in good yield via cyclometalation of the imine ligand (R)-PhMeC鈺怤CHMePh (L⁴) with [(畏⁵-C₅Me₅)IrCl₂]₂ in the presence of 2 equiv of silver triflate per ligand. NMR and X-ray analyses of (R_C)-5 indicated that the C鈺怤 moiety was endo as in 3, 4, and 4鈥?/b>; however, two diastereomers in equimolar amounts were identified in solution, in contrast to the case for the pyrroline complexes.