Bidentate diphosphoramidites with a piperazine group as ligands for hydroformylation

Abstract

The invention relates to Rh, Ru, Co and Ir complexes comprising bidentate diphosphoramidites as ligands and to the use thereof as catalysts for the hydroformylation of olefins. The invention also relates to a process for preparing an aldehyde from an olefin using the complexes or ligands mentioned.

Claims

1. Complex comprising Rh, Ru, Co or Ir and a compound of one of the general formulae (I) and (II) ##STR00009## where R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9, R.sup.10, R.sup.11, R.sup.12, R.sup.13, R.sup.14, R.sup.15, R.sup.16, R.sup.17, R.sup.18, R.sup.19, R.sup.20 are each independently selected from H, (C.sub.1-C.sub.12)-alkyl, O(C.sub.1-C.sub.12)-alkyl, (C.sub.6-C.sub.20)-aryl, O(C.sub.6-C.sub.20)-aryl, halogen, COO(C.sub.1-C.sub.12)-alkyl, CONH(C.sub.1-C.sub.12)-alkyl, CO(C.sub.1-C.sub.12)-alkyl, CO(C.sub.6-C.sub.20)-aryl, COOH, OH, N[(C.sub.1-C.sub.12)-alkyl].sub.2; and R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9, R.sup.12, R.sup.13, R.sup.14, R.sup.15, R.sup.16, R.sup.17, R.sup.18, R.sup.19 are each independently selected from H, (C.sub.1-C.sub.12)-alkyl, O(C.sub.1-C.sub.12)-alkyl, (C.sub.6-C.sub.20)-aryl, O(C.sub.6-C.sub.20)-aryl, halogen, COO(C.sub.1-C.sub.12)-alkyl, CONH(C.sub.1-C.sub.12)-alkyl, CO(C.sub.1-C.sub.12)-alkyl, CO(C.sub.6-C.sub.20)-aryl, COOH, OH, N[(C.sub.1-C.sub.12)-alkyl].sub.2.

2. Complex according to claim 1, comprising Rh.

3. Compound according to claim 1, characterized in that R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9, R.sup.10, R.sup.11, R.sup.12, R.sup.13, R.sup.14, R.sup.15, R.sup.16, R.sup.17, R.sup.18, R.sup.19, R.sup.20 are each independently selected from H, (C.sub.1-C.sub.12)-alkyl, O(C.sub.1-C.sub.12)-alkyl, (C.sub.6-C.sub.20)-aryl, O(C.sub.6-C.sub.20)-aryl, -halogen.

4. Complex according to claim 1, characterized in that R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9, R.sup.10, R.sup.11, R.sup.12, R.sup.13, R.sup.14, R.sup.15, R.sup.16, R.sup.17, R.sup.18, R.sup.19, R.sup.20 are each independently selected from H, (C.sub.1-C.sub.12)-alkyl, O(C.sub.1-C.sub.12)-alkyl, (C.sub.6-C.sub.20)-aryl, O(C.sub.6-C.sub.20)-aryl.

5. Complex according to claim 1, characterized in that R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9, R.sup.12, R.sup.13, R.sup.14, R.sup.15, R.sup.16, R.sup.17, R.sup.18, R.sup.19 are each independently selected from H, (C.sub.1-C.sub.12)-alkyl, O(C.sub.1-C.sub.12)-alkyl, (C.sub.6-C.sub.20)-aryl, O(C.sub.6-C.sub.20)-aryl, -halogen.

6. Complex according to claim 1, characterized in that R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9, R.sup.12, R.sup.13, R.sup.14, R.sup.15, R.sup.16, R.sup.17, R.sup.18, R.sup.19 are each independently selected from H, (C.sub.1-C.sub.12)-alkyl, O(C.sub.1-C.sub.12)-alkyl, (C.sub.6-C.sub.20)-aryl, O(C.sub.6-C.sub.20)-aryl.

7. Complex according to claim 1, characterized in that R.sup.1, R.sup.2, R.sup.4, R.sup.7, R.sup.9, R.sup.10, R.sup.11, R.sup.12, R.sup.14, R.sup.17, R.sup.19, R.sup.20 are each H.

8. Complex according to claim 1, characterized in that R.sup.2, R.sup.4, R.sup.7, R.sup.9, R.sup.12, R.sup.14, R.sup.17, R.sup.19 are each H.

9. Complex according to claim 1, characterized in that the compound of one of the formulae (I) and (II) is selected from the compounds (4), (5), (6) and (7) ##STR00010##

10. A process for hydroformylation, comprising: introducing the complex according to claim 1 as a catalyst.

11. Process for preparing an aldehyde, comprising the process steps of: a) initially charging an olefin, b) adding a complex according to claim 1 and a catalyst precursor comprising an Rh, Ru, Co or Ir complex, c) feeding in hydrogen and carbon monoxide, d) heating the reaction mixture, with conversion of the olefin to an aldehyde.

12. Process according to claim 11, characterized in that the catalyst precursor comprises a ligand selected from acetylacetonate, acetate and chloride.

13. Process according to claim 11, characterized in that the catalyst precursor is Rh(acac)(CO).sub.2.

14. Process for preparing an aldehyde, comprising the process steps of: a) initially charging an olefin, b) adding a compound of one of the formulae (I) and (II) according to claim 1 and a catalyst precursor comprising an Rh, Ru, Co or Ir complex, c) feeding in hydrogen and carbon monoxide, d) heating the reaction mixture, with conversion of the olefin to an aldehyde.

15. Process according to claim 14, characterized in that the catalyst precursor comprises a ligand selected from acetylacetonate, acetate and chloride.

16. Process according to claim 14, characterized in that the catalyst precursor is Rh(acac)(CO).sub.2.

Description

EXAMPLES

(1) The examples which follow illustrate the invention.

(2) General Methods

(3) All reactions were conducted under an inert atmosphere (5.0 argon) using standard Schlenk methodology. The solvents were dried by conventional methods and distilled under argon. If possible, the reactions were monitored by NMR spectroscopy. The yields reported below are isolated yields; melting points are uncorrected.

(4) NMR spectra were recorded at room temperature with a Bruker AV 300 or AV 400 MHz spectrometer. The chemical shifts are in ppm relative to TMS; solvent signals (dichloromethane, .sub.H=5.32 ppm, .sub.C=53.8 ppm; tetrahydrofuran .sub.H=3.58; 1.73 ppm; .sub.C=67.5; 25.37 ppm) were used as secondary reference for .sup.1H and .sup.13C NMR spectroscopy. For the .sup.31P NMR spectra, external H.sub.3PO.sub.4 was used as standard.

(5) The IR spectra were recorded on a Nicolet 380 FT-IR. High-resolution mass spectrometry (HRMS) was recorded on an Agilent 6210 E1969A TOF spectrometer. Only the measurements with an average deviation from the theoretical mass of 2 mDa were considered to be correct.

(6) X-ray diffraction data of single crystals of the compounds 6 were recorded on a Bruker APEX II Kappa Duo diffractometer. The structures were solved by direct methods by means of the SHELXS-97 program (G. M. Sheldrick, Acta. Crystallogr. Sect. A. 64 (2008) 112-122) and refined by the full matrix least squares method on F.sup.2 by means of the SHELXL-2014 program (G. M. Sheldrick, Acta. Crystallogr. Sect. C. 71 (2015) 3-8).

(7) Gas chromatography was conducted on an HP 5890 Series II using a PONA column (0.5 mm; length 50 m; diameter 0.2 mm). All reactions were monitored by thin layer chromatography (silica gel 60, F.sub.254, E. Merck KGAG). The solvent systems used (v/v) were: hexane-CH.sub.2Cl.sub.2 1:1 (A.sub.1), or 5:1 (A.sub.2); hexane-EtOAc 99:1 (B.sub.1). Detection was effected by UV fluorescence (=254 nm, =365 nm).

(8) Preparative flash chromatography was conducted by using packed columns (silica gel, RediSep) with a CombiFlash R.sub.f system (Teledyne ISCO).

(9) Synthesis of the Phosphorochloridites 1-3

(10) The phosphorochloridites 1 (E. Benetskiy, S. Lhr, M. Vilches-Herrera, D. Selent, H. Jiao, L. Domke, K. Dyballa, R. Franke, A. Brner, ACS Catal. 4 (2014) 2130-2136), 2 [V. N. Tsarev, A. A. Kabro, S. K. Moiseev, V. N. Kalinin, O. G. Bondarev, V. A. Davankov, K. N. Gavrilov, Russ. Chem. Bull., Int. Ed. 53 (2004) 814-818; D. J. Frank, A. Franzke, A. Pfaltz, Chem. Eur. J. 19 (2013) 2405-2415; O. Lot, I. Suisse1, A. Mortreux, F. Agbossou, J. Mol. Catal. A: Chem. 164 (2000) 125-130] and 3 (L. P. J. Burton, U.S. Pat. No. 4,739,000 A (1988)) were prepared according to the literature.

(11) ##STR00005##
Synthesis of the Phosphoramidites 4, 5 and 6

(12) For general procedure see B. L. Feringa, J. F. Teichert, Angew. Chem. Int. Ed. 49 (2010) 2486-2528; E. Balaraman, K. C. Kumara Swamy, Tetrahedron: Asymmetry 18 (2007) 2037-2048; M. Rodriguez i Zubiri, A. M. Z. Slawin, M. Wainwright, J. Derek Woollins, Polyhedron. 21 (2002) 1729-1736.

(13) A solution of the corresponding phosphorochloridites (2.0 mmol) in THF (20 ml) was added dropwise over a period of 30 min to an ice-cooled solution of the amine (1.0 mmol) and triethylamine (4.0 mmol) in THF (30 ml). After 15 min, the solution was allowed to warm up gradually to room temperature and the stirring was continued overnight; during this time, triethylammonium hydrochloride precipitated out of the colourless solution and was removable by filtration. After the solvent had been removed under reduced pressure, the crude product was purified by flash chromatography, and it was possible to isolate the amidites as white solids. All ligands are readily available and can be prepared on the gram scale.

(14) ##STR00006##

1,4-Bis(2,4,8,10-tetra-tert-butyldibenzo[d,f][1,3,2]dioxaphosphepin-6-yl)piperazine (4)

(15) See a) M. Rasberger, EP 5500 A1. (1979); b) M. Rasberger, U.S. Pat. No. 4,301,061 A. (1981); c) T. Shinya, P. Yukihiro, S. Motohiko, F. Kanako, S. Manji, Y. Tetsuo, Jpn. Kokai Tokkyo Koho, J P 07070158 A. (1995).

(16) Yield: 67%; white crystals; m.p. 341-343 C. (decomposition); R.sub.f 0.42 (system B.sub.1); .sup.31P-NMR (CD.sub.2Cl.sub.2): 143.48; .sup.1H-NMR (CD.sub.2Cl.sub.2; 300.13 MHz): 7.41; 7.13 (2br.s, 8H, ArH), 3.10-2.75 (m, 8H, NCH.sub.2); 1.47; 1.34 (2s, 72H, C(CH.sub.3).sub.3); .sup.13C-NMR (OD.sub.2Cl.sub.2; 75.46 MHz): 147.48 (d, .sup.2J.sub.C,P=5.68 Hz; ArCOP); 146.49; 140.19; 132.88 (ArCC), 126.41; 124.59 (ArCH); undetectable (NCH.sub.2); 35.68; 34.87 (C(CH.sub.3).sub.3); 31.61; 31.06; 31.02 (C(CH.sub.3).sub.3); HRMS (ESI) calc'd for [M+H].sup.+ C.sub.60H.sub.88N.sub.2O.sub.4P.sub.2: 963.6292; found: 963.6293; calc'd for [M+Na].sup.+ C.sub.60H.sub.88N.sub.2O.sub.4P.sub.2: 985.6112; found: 985.6117; elemental analysis calc. for C.sub.60H.sub.88N.sub.2O.sub.4P.sub.2(%): C, 74.81 (75.06); H, 9.21 (9.26); N, 2.91 (2.72); P, 6.42 (6.32).

1,4-Bis(dibenzo[d,f][1,3,2]dioxaphosphepin-6-yl)piperazine (5)

(17) Yield: 55%; white crystals; m.p. 209-210 C.; R.sub.f 0.35 (system A.sub.1); .sup.31P-NMR (CD.sub.2Cl.sub.2): 146.0; .sup.1H-NMR (CD.sub.2Cl.sub.2; 300.13 MHz): 7.49 (dd, 4H, J.sub.H,H=7.64 Hz; J.sub.H,H=1.74 Hz; ArH); 7.42-7.37; 7.31-7.19 (2m, 12H, ArH); 3.05-3.03 (m, 8H, NCH.sub.2); .sup.13C-NMR (CD.sub.2Cl.sub.2; 75.46 MHz): 151.56 (d, .sup.2J.sub.C,P=4.37 Hz; ArCOP); 131.38 (d, .sup.3J.sub.C,P=2.91 Hz; ArCC); 130.02; 129.65; 125.06; 122.21 (ArCH); 45.90-45.58 (m, .sup.2J.sub.C,P=18.94 Hz; .sup.3J.sub.C,P=4.37 Hz; NCH.sub.2); HRMS (ESI) calc'd for [M+H].sup.+ C.sub.28H.sub.24N.sub.2O.sub.4P.sub.2: 515.1284; found: 515.1283; elemental analysis calc. for C.sub.28H.sub.24N.sub.2O.sub.4P.sub.2(%): C, 65.37 (65.51); H, 4.70 (4.73); N, 5.45 (5.52); P, 12.04 (11.88).

Tetrakis(2,4-di-tert-butylphenyl)piperazine-1,4-diyl bis(phosphonite) (6)

(18) See M. Fryberg, V. Weiss, EP 0070254 A1. (1983).

(19) Yield: 62.5%; white crystals; m.p. 174-175 C.; R.sub.f 0.2 (system A.sub.2); .sup.31P-NMR (CD.sub.2Cl.sub.2): 133.3; .sup.1H-NMR (OD.sub.2Cl.sub.2; 300.13 MHz): 7.39 (d, 4H, J.sub.H,H=2.36 Hz; ArH); 7.10 (qd, 8H, 8.40 Hz; J.sub.H,H=2.40 Hz; ArH); 3.37-3.36 (m, 8H, NCH.sub.2); 1.43; 1.33 (2s, 72H, C(CH.sub.3).sub.3); .sup.13C-NMR (CD.sub.2Cl.sub.2; 100.61 MHz): 151.10 (d, .sup.2J.sub.C,P=8.37 Hz; ArCOP); 144.85; 131.33 (ArCC); 124.66; 123.73 (ArCH); 117.79 (d, .sup.3J.sub.C,P=22.31 Hz; ArCH); 45.11-44.86 (m, .sup.2J.sub.C,P=19.52 Hz; .sup.3J.sub.C,P=5.58 Hz; NCH.sub.2); 35.33; 34.67 (C(CH.sub.3).sub.3); 31.61; 30.23 (C(CH.sub.3).sub.3); HRMS (ESI) calc'd for [M+H].sup.+ C.sub.60H.sub.92N.sub.2O.sub.4P.sub.2: 967.6605; found: 967.6622; calc'd for [M+Na].sup.+ C.sub.60H.sub.92N.sub.2O.sub.4P.sub.2: 989.6425; found: 989.6432; elemental analysis calc. for C.sub.60H.sub.92N.sub.2O.sub.4P.sub.2 (%): C, 74.50 (74.53); H, 9.59 (9.55); N, 2.90 (2.91); P, 6.40 (6.46). Single crystals were obtained by gradually evaporating a concentrated solution of dichloromethane.

(20) Synthesis of Phosphoramidite 7: General Method

(21) See Y. H. Choi, J. Y. Choi, H. Y. Yang, Y. H. Kim, Tetrahedron: Asymmetry. 13 (2002) 801-804; M. Vuagnoux-d'Augustin, A. Alexakis, Chem. Eur. J. 13 (2007) 9647-9662; S. Lhr, J. Holz, A. Brner, Chem Cat Chem. 3 (2011) 1708-1730.

(22) A solution of the amine (1.0 mmol) and triethylamine (5.0 mmol) in THF (5 ml) is added dropwise to phosphorus trichloride (2.0 mmol) at 0 C. The reaction mixture was left to warm up to room temperature and to stir for a further three hours. The resulting HCl gas was driven out of the reaction vessel using a gentle argon stream. The clear solution was concentrated and dried azeotropically with toluene (three times). The resulting residue was used directly in the next step without further purification. The oily crude product was dissolved in THF (20 ml) and cooled to 0 C. A solution of phenol (4.0 mmol) and triethylamine (5.0 mmol) in THF (5 ml) was then added dropwise to the stirred solution. The reaction mixture was brought gradually to room temperature and the stirring was continued overnight. The precipitate was filtered off and the solution obtained was concentrated. The crude products were purified by flash chromatography and the pure amidites 7 were obtained as a white solid.

(23) ##STR00007##
Tetraphenylpiperazine-1,4-diylbis(phosphonite) (7)

(24) See Zh. Beishekeev, B. Ashimbaeva, T. Chyntemirova, K. Dzhundubaev, Zh. Anyrova, T. Toktobekova, Izvestiya Akademii Nauk Kirgizskoi SSR. 1 (1980) 37-39.

(25) Yield: 61%; white crystals; m.p. 110-111 C.; R.sub.f 0.40 (system A.sub.1); .sup.31 P-NMR (CD.sub.2Cl.sub.2): 136.94; .sup.1H-NMR (CD.sub.2Cl.sub.2; 300.13 MHz): 7.35-7.28; 7.12-7.04 (2m, 20H, ArH); 3.25-3.22 (m, 8H, NCH.sub.2); .sup.13C-NMR (CD.sub.2Cl.sub.2; 75.46 MHz): 154.01 (d, .sup.2J.sub.C,P=6.25 Hz; ArCOP); 130.02; 123.55; 120.54; 120.41 (ArCH, 2 signals are isochronous); 44.94-44.63 (m, .sup.2J.sub.C,P=18.21 Hz; .sup.3J.sub.C,P=4.79 Hz; NCH.sub.2); HRMS (ESI) calc'd for [M+H].sup.+ C.sub.28H.sub.28N.sub.2O.sub.4P.sub.2: 519.15971; found: 519.16035; calc'd for [M+Na].sup.+ C.sub.28H.sub.28N.sub.2O.sub.4P.sub.2: 541.14165; found: 541.1416; elemental analysis calc. for C.sub.28H.sub.28N.sub.2O.sub.4P.sub.2 (%): C, 64.86 (64.89); H, 5.44 (5.45); N, 5.40 (5.59); P, 11.95 (11.83).

(26) Synthesis of Rh (I) Complexes 8 and 9

(27) To a solution of Rh(acac)(CO).sub.2 (0.2 mmol) in toluene (5 ml) is added dropwise, at room temperature while stirring, a solution of the ligand (0.1 mmol) in toluene (5 ml) within 10 min. On completion of addition, the reaction solution is stirred for two hours and concentrated under reduced pressure. By washing the residue with hexane (6 ml) and drying at 60 C. over three hours, the spectroscopically pure products are obtained.

(28) ##STR00008##

(29) FIG. 5. Rh complexes 8 and 9

(30) [Rh(Acac)(CO)].sub.2(4) Complex (8)

(31) Yield: quantitative; yellow powder; .sup.31P-NMR (CD.sub.2Cl.sub.2): 141.80 (br. d, .sup.1J.sub.P,Rh=276.95 Hz); IR: (CO) 2000.3 cm.sup.1; .sup.1H-NMR (THF-d8; 300.13 MHz): 7.37 (d, 4H, J.sub.H,H=1.83 Hz; ArH); 7.04 (br. s, 4H, J.sub.H,H=1.64 Hz; ArH); 5.34 (s, 2H, CH.sub.acac); 3.03-2.28 (m, 8H, NCH.sub.2); 1.83 (s, 6H, Me.sub.acac); 1.77 (br. s, 6H, Me.sub.acac); 1.41; 1.23 (2s, 72H, C(CH.sub.3).sub.3); .sup.13C-NMR (THF-d8; 75.46 MHz): 188.56; 187.58 (2d, J.sub.C,Rh=29.15 Hz; CO); 187.34; 183.73 (CO.sub.acac); 146.28 (ArCOP); 145.87 (d, J.sub.C,P=9.48 Hz; ArCC); 149.51; 131.28; 127.16; 124.22 (ArCH); 99.54 (CH.sub.acac); undetectable (NCH.sub.2); 34.95; 33.89 (C(CH.sub.3).sub.3); 30.62; 30.39 (C(CH.sub.3).sub.3); 26.51 (Me.sub.acac); 26.02 (d, .sup.5J.sub.C,Rh=8.16 Hz; Me.sub.acac); HRMS (ESI) calc'd for [M+Na-2H].sup.+ C.sub.72H.sub.102N.sub.2O.sub.10P.sub.2Rh.sub.2: 1445.2015; found: 1445.50111; elemental analysis calc. for C.sub.72H.sub.104N.sub.2O.sub.10P.sub.2Rh.sub.2 (%): C, 60.67 (60.82); H, 7.35 (7.33); N, 1.97 (1.93); P, 4.35 (4.45); Rh, 14.44 (14.30).

(32) [Rh(Acac)(CO)].sub.2(6) Complex (9)

(33) Yield: quantitative; yellow powder; .sup.31P-NMR (CD.sub.2Cl.sub.2): 128.70 (d, .sup.1J.sub.P,Rh=258.56 Hz); IR: (CO) 1992.2 cm.sup.1; .sup.1H-NMR (CD.sub.2Cl.sub.2; 300.13 MHz): 7.49 (dd, 4H, J.sub.H,H=8.45 Hz; J.sub.H,H=1.41 Hz; ArH); 7.31 (br. d, 4H, J.sub.H,H=1.64 Hz; ArH); 7.04 (dd, 4H, J.sub.H,H=8.45 Hz; J.sub.H,H=2.46 Hz; ArH); 5.35 (s, 2H, CH.sub.acac); 3.70-3.04 (m, 8H, NCH.sub.2); 1.89; 1.52 (2s, 12H, Me.sub.acac); 1.29; 1.23 (2s, 72H, C(CH.sub.3).sub.3); .sup.13C-NMR (CD.sub.2Cl.sub.2; 75.46 MHz): 188.56; 187.58 (2d, J.sub.C,Rh=31.58 Hz; CO); 188.29; 185.84 (CO.sub.acac); 149.53 (d, .sup.2J.sub.C,P=3.20 Hz; ArCOP); 146.01 (ArCC); 138.89 (d, .sup.3J.sub.C,P=5.88 Hz; ArCC); 124.77; 123.35 (ArCH); 119.75 (J.sub.C,P=9.61 Hz; ArCH); 101.03 (CH.sub.acac); 46.86 (NCH.sub.2); 35.31; 34.77 (C(CH.sub.3).sub.3); 31.68; 30.32 (C(CH.sub.3).sub.3); 27.60 (d, .sup.5J.sub.C,Rh=7.68 Hz; Me.sub.acac); 26.84 (Me.sub.acac); HRMS (ESI) calc'd for [M+Na-2H].sup.+ C.sub.72H.sub.106N.sub.2O.sub.4P.sub.2Rh.sub.2: 1449.5325; found: 1449.5297; elemental analysis calc. for C.sub.72H.sub.108N.sub.2O.sub.4P.sub.2Rh.sub.2 (%): C, 60.50 (60.62); H, 7.62 (7.52); N, 1.96 (1.91); P, 4.33 (4.40); Rh, 14.40 (14.36).

(34) Hydroformylation Methods

(35) The hydroformylation experiments were conducted in a 200 ml autoclave equipped with a thermocouple, a Bronkhorst HITEC mass flow meter and a Bronkhorst pressure regulator, at 120 C. and a pressure of 50 bar of synthesis gas (99.997%; CO/H.sub.2=1:1). The reaction was effected at a constant pressure over a period of four hours. The autoclave together with the storage vessel for the olefin addition was purged repeatedly with argon before the catalyst solution (=metal complex+ligand+solvent) was introduced into the reactor and the olefin to the reservoir vessel (argon countercurrent). In a typical experiment, olefin (15 ml) and catalyst solution (41 ml) were used with olefin/rhodium ratio of 2000/1. The catalyst solution was heated to the desired reaction temperature under synthesis gas for 30 minutes. After the addition of olefin, the pressure was kept at 50 bar and the gas consumption was measured with a mass flow meter. After four hours, the autoclave was cooled down to room temperature and the pressure was released. The product analysis was effected by gas chromatography; for this purpose, the reaction solution (1 ml) was diluted with n-pentane (10 ml) and toluene was used as internal standard.

(36) Experiments were conducted in each case with n-octenes (EVONIK Industries AG, octene isomer mixture of 1-octene: 3.3%; cis-+trans-2-octene: 48.5%; cis-+trans-3-octene: 29.2%; cis-+trans-4-octene: 16.4%; structurally isomeric octenes: 2.6%), 1-octene or 2-pentene as reactants. The yields and n/iso ratios achieved are shown in Tables 1 to 3. As apparent from the experimental results, the complexes according to the invention are suitable as catalysts for the hydroformylation of olefins, with which virtually quantitative yields can be achieved. Moreover, it is possible via selection of the ligands according to the invention to achieve a high n or iso selectivity.

(37) TABLE-US-00001 TABLE 1 Hydroformylation of n-octene with the bidentate diphosphoramidites 4 and 6 n selectivity Entry Ligand L/Rh Yield (%) (%) 1 4 2 98.9 18.7 2 6 2 91.7 16.9

(38) TABLE-US-00002 TABLE 2 Hydroformylation of 1-octene with the bidentate diphosphoramidites 4, 5 and 7 n selectivity Entry Ligand L/Rh Yield (%) (%) 1 4 2 99.6 52.8 2 5 2 85.3 75.2 3 7 2 28.5 69.0

(39) TABLE-US-00003 TABLE 3 Hydroformylation of 2-pentene with the bidentate diphosphoramidites 5 and 6 n selectivity Entry Ligand L/Rh Yield (%) (%) 1 5 2 59.4 20.3 2 6 2 100 36.6

(40) As the results show, the n/iso ratio can be controlled with the aid of the novel ligands.