117968-50-0Relevant articles and documents
Internal alkene hydroaminations catalyzed by zirconium(IV) complexes and asymmetric alkene hydroaminations catalyzed by yttrium(III) complexes
Kim, Hyunseok,Kim, Young Kwan,Shim, Jun Hwan,Kim, Misook,Han, Mijung,Livinghouse, Tom,Lee, Phil Ho
, p. 2609 - 2618 (2006)
The thiophosphinic amide 2 was prepared in 68% yield by the reaction of 2,2-dimethyl-1,3-propanediamine with diisopropylchlorophosphine followed by the addition of sulfur. Attachment of the proligand 2 to zirconium was achieved by direct metalation with Zr(NMe2)4 in benzene-d6 or toluene-d8 to afford complex 3 via elimination of dimethylamine. The neutral Zr(IV) complex 3 has been shown to be an effective precatalyst for intramolecular alkene hydroaminations that provide cyclic amines in good to excellent yields. A variety of chiral ligands (20, 22, 24, and 25-30) were prepared for asymmetric internal alkene hydroaminations. Metalation of chiral ligands to yttrium was accomplished with Y[N-(TMS)2]3 in benzene-d6 or toluene-d8 to give complexes. Treatment of 7 with 5 mol% of 33 in benzene-d6 (25°C, 18 h) or toluene-d 8 (25°C, 15 h) afforded 2,4,4-trimethylpyrrolidine 14 in 95% yield (61% ee).
Non-metallocene rare earth metal catalysts for the diastereoselective and enantioselective hydroamination of aminoalkenes
Hultzsch, Kai C.,Gribkov, Denis V.,Hampel, Frank
, p. 4441 - 4452 (2005)
In this short review we summarize our work on new cyclopentadienyl-free rare earth metal catalysts for the diastereoselective and enantioselective hydroamination of aminoalkenes. Non-metallocene rare earth metal catalysts based on diamidoamine, biphenolate and binaphtholate ligands are readily available through alkane and amine elimination procedures. Diamidoamine yttrium complexes are efficient catalysts for the highly diastereoselective cyclization of 1-methyl-pent-4-enylamine to yield trans-2,5-dimethyl-pyrroldine with trans to cis ratios of up to 23:1. The X-ray crystal structural analysis of [((2,6-Et2C6H3NCH2CH 2)2NMe)Y{N(SiMe3)2}] is reported in which yttrium is coordinated in a highly distorted tetrahedral fashion. 3,3′-Di-tert-butyl substituted biphenolate complexes tend to form phenolate-bridged hetero- and homochiral dimers. The low steric demand of the tert-butyl substituents resulted also in low enantioselectivities in hydroamination/cyclization reactions. Binaphtholate complexes with sterically more demanding tris(aryl)silyl substituents were more efficient catalysts; giving enantioselectivities of up to 83% ee. These catalysts could also be applied in kinetic resolution of chiral aminoalkenes giving krel values as high as 16. Catalyst activities strongly depend on the reactivity of the leaving group which is protolytically exchanged for the substrate during the initiation step. Complexes with bis(dimethylsilyl)amido ligand initiate rather sluggishly because of the low basicity of this amido ligand and appreciable catalytic activity is only observed at elevated temperatures. Aryl and Alkyl complexes showed significant better rates comparable in magnitude to lanthanocene catalysts.
Intramolecular alkene hydroaminations catalyzed by simple amido derivatives of the Group 3 metals
Kim, Young Kwan,Livinghouse, Tom,Bercaw, John E.
, p. 2933 - 2935 (2001)
Bis(trimethylsilyl) amides of the type Ln[N(TMS) 2]3 have been found to be competent catalysts for representative intramolecular alkene hydroaminations. The catalytic cyclization of an aminodiene proceeds in a stepwise manner to provide the corresponding monocycle and bicycle in a highly stereocontrolled manner.
Intramolecular hydroamination of functionalized alkenes and alkynes with a homogenous zinc catalyst
Zulys, Agustino,Dochnahl, Maximilian,Hollmann, Dirk,Loehnwitz, Karolin,Herrmann, Jost-Steffen,Roesky, Peter W.,Blechert, Siegfried
, p. 7794 - 7798 (2005)
(Chemical Equation Presented) Simple and versatile: A new zinc complex catalyzes the intramolecular hydroamination of nonactivated alkynes and alkenes (see example in scheme; {(iPr)2ATI} = N-isopropyl-2-(isopropylamino) troponiminato). The catalyst is relatively robust, exhibits excellent activities, and tolerates various functional groups such as ethers, thioethers, and amides.
Reactivity of functionalized indoles with rare-earth metal amides. Synthesis, characterization and catalytic activity of rare-earth metal complexes incorporating indolyl ligands
Feng, Zhijun,Wei, Yun,Zhou, Shuangliu,Zhang, Guangchao,Zhu, Xiancui,Guo, Liping,Wang, Shaowu,Mu, Xiaolong
, p. 20502 - 20513 (2015/12/05)
The reactivity of several functionalized indoles 2-(RNHCH2)C8H5NH (R = C6H5 (1), tBu (2), 2,6-iPr2C6H3 (3)) with rare-earth metal amides is described. Reactions of 1 or 2 with [(Me3Si)2N]3RE(μ-Cl)Li(THF)3 (RE = Eu, Yb) respectively produced the europium complexes [2-(C6H5NCH)C8H5N]2Eu[N(SiMe3)2] (4) and [2-(tBuNCH)C8H5N]Eu[N(SiMe3)2]2 (5), and the ytterbium complex [2-(tBuNCH)C8H5N]2Yb[N(SiMe3)2] (6), containing bidentate anionic indolyl ligands via dehydrogenation of the amine to the imine. In contrast, reactions of the more sterically bulky indole 3 with [(Me3Si)2N]3RE(μ-Cl)Li(THF)3 afforded complexes [2-(2,6-iPr2C6H3NCH2)C8H5N]RE[N(SiMe3)2](THF)2 (RE = Yb (7), Y (8), Er (9), Dy (10)) with the deprotonated indolyl ligand. While reactions of 3 with yttrium and ytterbium amides in refluxing toluene respectively gave the complexes [2-(2,6-iPr2C6H3NCH)C8H5N]3Y (11) and [2-(2,6-iPr2C6H3NCH)C8H5N]2YbII(THF)2 (12), along with transformation of the amino group to the imino group, and also with a reduction of Yb3+ to Yb2+ in the formation of 12. Reactions of 3 with samarium and neodymium amides provided novel dinuclear complexes {[μ-η5:η1:η1-2-(2,6-iPr2C6H3NCH2)C8H5N]RE[N(SiMe3)2]}2 (RE = Sm (13), Nd (14)) having indolyl ligands in μ-η5:η1:η1 hapticities. The pathway for the transformation of the amino group to the imino group is proposed on the basis of the experimental results. The new complexes displayed excellent activity in the intramolecular hydroamination of aminoalkenes.
Bis(imidazolin-2-iminato) rare earth metal complexes: Synthesis, structural characterization, and catalytic application
Trambitas, Alexandra G.,Melcher, Daniel,Hartenstein, Larissa,Roesky, Peter W.,Daniliuc, Constantin,Jones, Peter G.,Tamm, Matthias
experimental part, p. 6753 - 6761 (2012/08/07)
Reaction of anhydrous rare earth metal halides MCl3 with 2 equiv of 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-imine (ImDippNH) and 2 equiv of trimethylsilylmethyl lithium (Me3SiCH2Li) in THF furnished the complexes [(ImDippN)2MCl(THF)n] (M = Sc, Y, Lu). The molecular structures of all three compounds were established by single-crystal X-ray diffraction analyses. The coordination spheres around the pentacoordinate metal atoms are best described as trigonal bipyramids. Reaction of YbI2 with 2 equiv of LiCH 2SiMe3 and 2 equiv of the imino ligand ImDippNH in tetrahydrofuran did not result in a divalent complex, but instead the Yb(III) complex [(ImDippN)2YbI(THF)2] was obtained and structurally characterized. Treatment of [(ImDippN) 2MCl(THF)n] with 1 equiv of LiCH2SiMe 3 resulted in the formation of [(ImDippN) 2M(CH2SiMe3)(THF)n]. The coordination arrangement of these compounds in the solid state at the metal atoms is similar to that found for the starting materials, although the introduction of the neosilyl ligand induces a significantly greater distortion from the ideal trigonal-bipyramidal geometry. [(ImDippN) 2Y(CH2SiMe3)(THF)2] was used as precatalyst in the intramolecular hydroamination/cyclization reaction of various terminal aminoalkenes and of one aminoalkyne. The complex showed high catalytic activity and selectivity. A comparison with the previously reported dialkyl yttrium complex [(ImDippN)Y(CH2SiMe3) 2(THF)3] showed no clear tendency in terms of activity.
Highly active and diastereoselective N,O- and N,N-yttrium complexes for intramolecular hydroamination
Lauterwasser, Frank,Hayes, Paul G.,Piers, Warren E.,Schafer, Laurel L.,Braese, Stefan
experimental part, p. 1384 - 1390 (2011/06/26)
The intramolecular hydroamination of aminoalkynes and unactivated aminoalkenes catalyzed by yttrium N,O- and N,N-complexes has been investigated. The N,N-yttrium complexes are highly active, catalyzing the conversion of a wide range of terminal aminoalkenes at room temperature, and internal aminoalkenes at elevated temperature, to yield pyrrolidine and piperidine products in high yields. A high diastereoselectivity of up to 23:1 is observed at 0°C with 1-methyl-4-pentenylamine as substrate.
Rare-earth metal alkyl, amido, and cyclopentadienyl complexes supported by Lmidazolin-2-iminato ligands: Synthesis, structural characterization, and catalytic application
Trambitas, Alexandra G.,Panda, Tarun K.,Jenter, Jelena,Roesky, Peter W.,Daniliuc, Constantin,Hrib, Cristian G.,Jones, Peter G.,Tamm, Matthias
experimental part, p. 2435 - 2446 (2010/05/15)
The rare earth metal dichlorides [(1)MCl2(THF)3] (2a, M = Sc; 2b, M = Y; 2c, M = Lu) and the gadolinium complex [(1)GdCl 2(THF)2]·[LiCl(THF)2] (2d), containing the 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-iminato ligand 1, proved to be versatile starting materials for the preparation of trimethylsilylmethyl ("neosilyl") and bis(thmethylsilyl)amido complexes [(1)M(CH 2SiMe3)2(THF)2] (3a-3d) and [(1)M(HMDS)2(THF)] [4a-4d, HMDS = hexamethyldisilazide, N(SiMe 3)2] and for the preparation of the benzyl complex [(1)Lu(CH2Ph)2(THF)2] (5c) by the reaction with LiCH2SiMe3, Na[N(SiMe3)2], and KCH2Ph, respectively. Treatment of 2a-2c with KCp* afforded the mono(pentamethylcyclopentadienyl) complexes [(1)Sc(Cp*)Cl(THF)] (6a), [(1)Y(Cp*)Cl(THF)2] (6b), and [(1)Lu(Cp*)Cl(THF)] (6c). In contrast, the gadolinocene complex [(1)Gd(Cp*)2(THF)] (7) was isolated from the reaction of 2d with 2 equiv of KCp*. The molecular structures of 3a-3d, 4b-THF, 4d, 5c, 6a, 6c, and 7-THF were determined by X-ray diffraction analyses, revealing the presence of exceptionally short metal-nitrogen bonds. The neosilyl complexes 3b and 3c showed high catalytic activity in the intramolecular hydroamination of aminoalkenes and aminoalkynes and in the hydrosilylation of 1-hexene and 1-octene with PhSiH3.
C2-symmetric zirconium Bis(Amidate) complexes with enhanced reactivity in aminoalkene hydroamination
Reznichenko, Alexander L.,Hultzsch, Kai C.
scheme or table, p. 24 - 27 (2010/03/04)
Binaphthalenedicarboxamide zirconium complexes exhibit significantly enhanced catalytic activity in aminoalkene hydroamination reactions with respect to substrate scope (substrates without gem-dialkyl activation; cyclization of aminoheptenes), catalyst loading (as low as 0.5 mol %) and reaction temperatures (as low as 70 °C) compared to previous group 4 metal-based hydroamination catalyst systems.
Intramolecular hydroamination of aminoalkenes by calcium and magnesium complexes: A synthetic and mechanistic study
Crimmin, Mark R.,Arrowsmith, Merle,Barrett, Anthony G. M.,Casely, Ian J.,Hill, Michael S.,Procopiou, Panayiotis A.
supporting information; experimental part, p. 9670 - 9685 (2011/03/20)
The β-diketiminate-stabilized calcium amide complex [{ArNC(Me)CHC(Me)NAr}Ca{N(SiMe3)2}-(THF)] (Ar = 2,6-diisopropylphenyl) and magnesium methyl complex [{ArNC(Me)CHC(Me)NAr}Mg(Me) (THF)] are reported as efficient precatalysts for hydroamination/cyclization of aminoalkenes. The reactions proceeded under mild conditions, allowing the synthesis of five-, six-, and seven-membered heterocyclic compounds. Qualitative assessment of these reactions revealed that the ease of catalytic turnover increases (i) for smaller ring sizes (5 > 6 > 7), (ii) substrates that benefit from favorable Thorpe-Ingold effects, and (iii) substrates that do not possess additional substitution on the alkene entity. Prochiral substrates may undergo diastereoselective hydroamination/cyclization depending upon the position of the existing stereocenter. Furthermore, a number of minor byproducts of these reactions, arising from competitive alkene isomerization reactions, were identified. A series of stoichiometric reactions between the precatalysts and primary amines provided an important model for catalyst initiation and suggested that these reactions are facile at room temperature, with the reaction of the calcium precatalyst with benzylamine proceeding with ΔG°(298 K) = -2.7 kcal mol-1. Both external amine/amide exchange and coordinated amine/amide exchange were observed in model complexes, and the data suggest that these processes occur via low-activation-energy pathways. As a result of the formation of potentially reactive byproducts such as hexamethyldisilazane, calcium-catalyst initiation is reversible, whereas for the magnesium precatalyst, this process is nonreversible. Further stoichiometric reactions of the two precatalysts with 1-amino-2,2-diphenyl-4-pentene demonstrated that the alkene insertion step proceeds via a highly reactive transient alkylmetal intermediate that readily reacts with N-H σ bonds under catalytically relevant conditions. The results of deuterium-labeling studies are consistent with the formation of a single transient alkyl complex for both the magnesium and calcium precatalysts. Kinetic analysis of the nonreversible magnesium system revealed that the reaction rate depends directly upon catalyst concentration and inversely upon substrate concentration, suggesting that substrate-inhibited alkene insertion is rate-determining.
