708268-52-4Relevant articles and documents
Direct ortho-C-H Aminoalkylation of 2-Substituted Pyridine Derivatives Catalyzed by Yttrium Complexes with N,N′-Diarylethylenediamido Ligands
Kundu, Abhinanda,Inoue, Mariko,Nagae, Haruki,Tsurugi, Hayato,Mashima, Kazushi
, p. 7332 - 7342 (2018)
A mixed ligated amidoyttrium complex, Y(NBn2)(L1)(THF)2 (8, L1 = N,N'-bis(2,6-diisopropylphenyl)ethylenediamine), served as a catalyst for addition of the ortho-pyridyl C(sp2) - H bond of 2-substituted pyridines to nonactivated imines; complex 8 showed superior catalytic performance compared with Y[N(SiMe3)2]3 (1) and Y[N(SiMe3)2]2(NBn2)(THF) (2). Concerning the reaction mechanism, we conducted a stoichiometric reaction of an alkylyttrium complex, Y(CH2SiMe3)(L1)(THF)2 (7), with 2-ethylpyridine (4e), giving a mixture of (η3-pyridylmethyl)yttrium complex 9 and (η2-pyridyl)yttrium complex 10 along with elimination of SiMe4. Furthermore, addition of N-(tert-butyl)-2-methylpropan-1-imine (5i) to the mixture of 9 and 10 afforded (pyridylmethylamido)yttrium complex 11 as a single product, and the catalytic activity of 11 was comparable to that of complex 8. Kinetic analysis of the aminoalkylation reaction in the presence/absence of HNBn2 revealed that the reaction rate in the presence of HNBn2 was four times faster than that without HNBn2 due to acceleration of the product-eliminating step from complex 11 by HNBn2 to regenerate amidoyttrium complex 8 and the product. In addition, we determined that the catalytic reaction obeyed a first-order rate dependence on the catalyst concentration, independent of the imine concentration, and a second-order rate dependence on the concentration of the pyridine substrate in the reaction system, both with and without HNBn2. An enantiomerically pure N,N'-diaryl-1,2-diphenylethylenediamido ligand was applied for the C(sp2) - H aminoalkylation reaction in combination with Lu(CH2SiMe3)3(THF)2 to give chiral aminoalkylated products in moderate yield with good enantioselectivity.
Alkyl complexes of rare-earth metal centers supported by chelating 1,1′-diamidoferrocene ligands: Synthesis, structure, and application in methacrylate polymerization
Eppinger, Joerg,Nikolaides, Katharina R.,Zhang-Presse, Mei,Riederer, Florian A.,Rabe, Gerd W.,Rheingold, Arnold L.
, p. 736 - 740 (2009/01/30)
Conversion of 1,1′-dianilinoferrocenes of the composition [3,4-R 2C5H2(NHPh)]2Fe (R = H, Ph) with 1 equiv of the rare-earth metal alkyl precursors Ln(THF)2(CH 2SiMe3)3 (Ln = Lu, Y) affords [R 4Fc(NPh)2]Ln(THF)2CH2SiMe 3 (1a-2b) in yields of 73-83%. The steric bulk of the ferrocene moiety induces a pronounced stabilization of the complexes in comparison to alkyl-bridged analogues. Correspondingly, the complexes 1a-2b are stable in solution at room temperature and were characterized by multinuclear NMR spectroscopy and elemental analysis. A single-crystal X-ray diffraction study was performed for complex 2b. The synthesized rare-earth metal alkyls embedded into a 1,1′-diamidoferrocene framework effectively initiate the polymerization of methyl methacrylate (MMA) at room temperature, producing isotactic enriched poly(methyl methacrylate) (PMMA). The properties of the produced PMMAs are mainly governed by the substitution patterns of the ferrocenyl backbone.
Yttrium complexes incorporating the chelating diamides {ArN(CH 2)xNAr}2- (Ar = C6H 3-2,6-iPr2, x = 2, 3) and their unusual reaction with phenylsilane
Avent, Anthony G.,Cloke, F. Geoffrey N.,Elvidge, Benjamin R.,Hitchcock, Peter B.
, p. 1083 - 1096 (2007/10/03)
Novel yttrium chelating diamide complexes [(Y{ArN(CH2) xNAr}(Z)(THF)n)y,] (Z = I, CH(SiMe 3)2, CH2Ph, H, N(SiMe3)2, OC6H3-2,6-tBu2-4-Me; x = 2, 3; n = 1 or 2; y = 1 or 2) were made via salt metathesis of the potassium diamides (x = 3 (3), x = 2 (4)) and yttrium triiodide in THF (5, 10), followed by salt metathesis with the appropriate potassium salt (6-9, 11-13, 15) and further reaction with molecular hydrogen (14). 6 and 11 (Z = CH(SiMe3) 2, x = 2, 3) underwent unprecedented exchange of yttrium for silicon on reaction with phenylsilane to yield (Si{ArN(CH2) xNAr}PhH) (x = 2 (16), 3) and (Si{CH(SiMe3) 2}PhH2).
