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DOI: 10.1055/s-2007-986651
Titanium and Zirconium Complexes with Helical Bis(phenolato) Ligands as Hydroamination Catalysts
Publikationsverlauf
Publikationsdatum:
12. September 2007 (online)
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Abstract
A racemic bisphenolato (OSSO)-type ligand that contains a trans-1,2-cyclohexanediyl backbone can be obtained in two steps from commercially available starting materials. In situ combination of this ligand with Ti(NMe2)4 or Zr(NMe2)4 results in the formation of bis(phenolato) complexes that catalyze hydroaminations of alkynes and alkenes.
Key words
alkynes - aminations - amines - homogenous catalysis - titanium
- For reviews, see:
-
1a
Chekulaeva IA.Kondratjeva LV. Russ. Chem. Rev. (Engl. Transl.) 1965, 34: 669 -
1b
Steinborn D.Taube R. Z. Chem. 1986, 26: 349 -
1c
Taube R. In Applied Homogeneous Catalysis with Organometallic CompoundsCornils B.Herrmann WA. Wiley-VCH; Weinheim: 1996. p.507 -
1d
Müller TE.Beller M. Chem. Rev. 1998, 98: 675 -
1e
Müller TE.Beller M. In Transition Metals for Organic Synthesis Vol. 2:Beller M.Bolm C. Wiley-VCH; Weinheim: 1998. p.316 -
1f
Haak E.Doye S. Chem. Unserer Zeit 1999, 33: 296 -
1g
Nobis M.Drießen-Hölscher B. Angew. Chem. Int. Ed. 2001, 40: 3983 ; Angew. Chem. 2001, 113, 4105 -
1h
Brunet JJ.Neibecker D. In Catalytic HeterofunctionalizationTogni A.Grützmacher H. Wiley-VCH; Weinheim: 2001. p.91 -
1i
Roesky PW.Müller TE. Angew. Chem. Int. Ed. 2003, 42: 2708 ; Angew. Chem. 2003, 115, 2812 -
1j
Bytschkov I.Doye S. Eur. J. Org. Chem. 2003, 935 -
1k
Hartwig JF. Pure Appl. Chem. 2004, 76: 507 -
1l
Alonso F.Beletskaya IP.Yus M. Chem. Rev. 2004, 104: 3079 -
1m
Doye S. Synlett 2004, 1653 -
1n
Odom AL. Dalton Trans. 2005, 225 -
1o
Hultzsch KC. Adv. Synth. Catal. 2005, 347: 367 -
1p
Hultzsch KC. Org. Biomol. Chem. 2005, 3: 1819 - For reviews, see:
-
2a
Pohlki F.Doye S. Chem. Soc. Rev. 2003, 32: 104 -
2b
Severin R.Doye S. Chem. Soc. Rev. 2007, 36: 1407 -
3a
Bexrud JA.Beard JD.Leitch DC.Schafer LL. Org. Lett. 2005, 7: 1959 -
3b
Kim H.Lee PH.Livinghouse T. Chem. Commun. 2005, 5205 -
3c
Müller C.Loos C.Schulenberg N.Doye S. Eur. J. Org. Chem. 2006, 2499 -
3d
Thomson RK.Bexrud JA.Schafer LL. Organometallics 2006, 25: 4069 -
3e
Lee AV.Schafer LL. Organometallics 2006, 25: 5249 -
3f
Kim H.Kim YK.Shim JH.Kim M.Han M.Livinghouse T.Lee PH. Adv. Synth. Catal. 2006, 348: 2609 -
3g
Stubbert BD.Marks TJ. J. Am. Chem. Soc. 2007, 129: 6149 -
4a
Watson DA.Chiu M.Bergman RG. Organometallics 2006, 25: 4731 -
4b
Wood MC.Leitch DC.Yeung CS.Kozak JA.Schafer LL. Angew. Chem. Int. Ed. 2007, 46: 354 ; Angew. Chem. 2007, 119, 358 - 5
Ma H.Spaniol TP.Okuda J. Angew. Chem. Int. Ed. 2006, 45: 7818 ; Angew. Chem. 2006, 118, 7982 - 6
Beckerle K.Manivannan R.Lian B.Meppelder G.-JM.Raabe G.Spaniol TP.Ebeling H.Pelascini F.Mülhaupt R.Okuda J. Angew. Chem. Int. Ed. 2007, 46: 4790 ; Angew. Chem. 2007, 119, 4874 - 7
Pastor SD.Denney DZ. J. Heterocycl. Chem. 1988, 25: 681 - 9
Caserio MC.Fisher CL.Kim JK. J. Org. Chem. 1985, 50: 4390 -
14a
Khedkar V.Tillack A.Beller M. Org. Lett. 2003, 5: 4767 -
14b
Tillack A.Khedkar V.Beller M. Tetrahedron Lett. 2004, 45: 8875 -
14c
Tillack A.Khedkar V.Jiao H.Beller M. Eur. J. Org. Chem. 2005, 5001 - 16
Sheldrick GM. SHELXTL-PLUS Bruker Analytical X-ray Division; Madison Wisconsin: 2001. - 17
Heutling A.Pohlki F.Doye S. Chem. Eur. J. 2004, 10: 3059
References and Notes
Experimental Procedure: S2Cl2 (16.88 g, 125 mmol) was added dropwise to a solution of 2,4-bis(α,α-dimethyl-benzyl)phenol (1, 82.62 g, 250 mmol) and TiCl4 (0.474 g, 2.5 mmol, 2.0 mol%) in toluene (180 mL) at -5 °C. The resulting mixture was stirred at -5 °C for 30 min and at r.t. for 72 h. Then, the mixture was washed with aq HCl (2 × 250 mL, c = 19%), sat. aq Na2CO3 solution and H2O. The organic layer was dried with MgSO4 and concentrated under vacuum. Crystallization from MeCN (1800 mL) gave analytically pure disulfide 2 (49.88 g, 69 mmol, 55%). 1H NMR (300 MHz, CD2Cl2): δ = 0.97 (s, 12 H), 1.04 (s, 12 H), 6.49-6.62 (m, 24 H). Anal. Calcd for C48H50O2S2 (723.0): C, 79.73; H, 6.97; S, 8.87. Found: C, 79.70; H, 6.93; S, 8.96.
10Experimental Procedure: Cyclohexene (4.6 g, 56 mmol) and BF3·OEt2 (0.5 mL) were added to a solution of disulfide 2 (20 g, 28 mmol) in a mixture of nitromethane (15 mL) and CH2Cl2 (15 mL) at -10 °C. The resulting mixture was stirred at -10 °C for 3 h and at r.t. for 72 h. Then, the mixture was washed with sat. aq NaHCO3 solution. The organic layer was dried with MgSO4 and concentrated under vacuum. Crystallization from a 4:1-mixture of MeCN and acetone (200 mL) gave analytically pure bis(phenolato) ligand rac-3 (21.68 g, 27 mmol, 96%). 1H NMR (500 MHz, CD2Cl2): δ = 1.02-1.06 (m, 4 H), 1.54-1.58 (m, 2 H), 1.64 (s, 12 H), 1.70 (s, 12 H), 1.70-1.74 (m, 2 H), 2.47-2.51 (m, 2 H), 6.83 (s, 2 H), 7.10-7.14 (m, 6 H), 7.15-7.22 (m, 8 H), 7.25-7.30 (m, 8 H), 7.37 (d, J = 2.1 Hz, 2 H). Anal. Calcd for C54H60O2S2 (805.2): C, 80.55; H, 7.51; S, 7.96. Found: C, 80.38; H, 7.51; S, 7.97.
11Colorless crystal(polyhedron), dimensions 0.42 × 0.18 × 0.10 mm3, crystal system triclinic, space group P1, Z = 2, a = 8.5820(2) Å, b = 16.3662(4) Å, c = 18.3078(5) Å, α = 73.1710(10)°, β = 83.3570(10)°, γ = 77.9890(10)°, V = 2403.18(10) Å3, ρ = 1.169 g/cm3, T = 200(2) K, Θmax = 25.42°, radiation Mo-Kα, λ = 0.71073 Å, 0.3° ω-scans with CCD area detector, covering a whole sphere in reciprocal space, 21011 reflections measured, 8802 unique [R(int) = 0.0883], 4564 observed [I >2σ(I)], intensities were corrected for Lorentz and polarization effects, an empirical absorption correction was applied using SADABS16 based on the Laue symmetry of the reciprocal space, µ = 0.15 mm-1, Tmin = 0.94, Tmax = 0.98, structure solved by direct methods and refined against F2 with a full-matrix least-squares algorithm using the SHELXTL-PLUS16 software package, 577 parameters refined, hydrogen atoms were treated using appropriate riding models, except for H1 and H2 at the oxygen atoms, which were refined isotropically, goodness of fit 0.98 for observed reflections, final residual values R1(F) = 0.062, wR(F2) = 0.115 for observed reflections, residual electron density -0.30 eÅ-3 to 0.24 eÅ-3. CCDC number 652550 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
12Experimental Procedure: TiCl4 (95 mg, 0.5 mmol) was added to a solution of rac-3 (402 mg, 0.5 mmol) in toluene (3 mL) at r.t. After the mixture had been stirred for 3 h at r.t., all volatiles (toluene, HCl) were removed under reduced pressure. The residue was washed with hexane. Crystallization from toluene gave complex rac-4 (456 mg, 0.49 mmol, 99%) as red-brown crystals. 1H NMR (500 MHz, CD2Cl2): δ = 0.64-0.72 (m, 2 H), 0.87-0.93 (m, 2 H), 1.46-1.48 (m, 2 H), 1.65 (s, 6 H), 1.68-1.69 (m, 2 H), 1.70 (s, 6 H), 1.73 (s, 6 H), 1.79-1.81 (m, 2 H), 1.85 (s, 6 H), 6.80 (d, J = 2.2 Hz, 2 H), 7.12-7.32 (m, 20 H), 7.56 (d, J = 2.1 Hz, 2 H). In order to avoid the formation of solid byproducts the reaction was performed in the absence of a base.
13Red-brown crystal(polyhedron), dimensions 0.20 × 0.16 × 0.05 mm3, crystal system monoclinic, space group C2/c, Z = 4, a = 28.177(3) Å, b = 11.1949(13) Å, c = 19.892(2) Å, β = 105.392(3)°, V = 6049.5(12) Å3, ρ = 1.215 g/cm3, T = 200(2) K, Θmax = 28.40°, radiation Mo-Kα, λ = 0.71073 Å, 0.3° ω-scans with CCD area detector, covering a whole sphere in reciprocal space, 31295 reflections measured, 7545 unique [R(int) = 0.0531], 5283 observed [I >2σ(I)], intensities were corrected for Lorentz and polarization effects, an empirical absorption correction was applied using SADABS16 based on the Laue symmetry of the reciprocal space, µ = 0.34 mm-1, Tmin = 0.93, Tmax = 0.98, structure solved by direct methods and refined against F2 with a full-matrix least-squares algorithm using the SHELXTL-PLUS16 software package, 488 parameters refined, hydrogen atoms were treated using appropriate riding models, goodness of fit 1.03 for observed reflections, final residual values R1(F) = 0.057, wR(F2) = 0.117 for observed reflections, residual electron density -0.20 eÅ-3 to 0.38 eÅ-3. CCDC number 652551 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
15General Procedure: A Schlenk tube equipped with a Teflon stopcock and a magnetic stirring bar was charged with Ti(NMe2)4 (27 mg, 0.12 mmol, 5.0 mol%), rac-3 (97 mg, 0.12 mmol, 5.0 mol%) and toluene (1.0 mL). After this mixture had been stirred for 30 min at r.t., the alkyne (2.40 mmol) and the amine (2.64 mmol) were added and the resulting mixture was heated to 105 °C for 24 h. Then the mixture was cooled to r.t. and a mixture of NaBH3CN (302 mg, 4.80 mmol) and ZnCl2 (326 mg, 2.40 mmol) in MeOH (10 mL) was added. After this mixture had been stirred at 25 °C for 20 h, CH2Cl2 (50 mL) and sat. Na2CO3 solution (20 mL) were added. The resulting mixture was filtered and the solid residue was washed with CH2Cl2 (50 mL). After extraction, the organic layer was separated. The aqueous layer was extracted with CH2Cl2 (6 × 50 mL). The combined organic layers were dried with Na2SO4. After concentration under vacuum, the residue was purified by flash chromatog-raphy (SiO2). All compounds were identified by comparison of the obtained 1H and 13C NMR spectra with those reported in the literature.17