Complexes of diphenyl selenoxides, use thereof and catalysis methods

Abstract

Novel complexes of diphenyl selenoxides and also use thereof and methods in which the complexes are used.

Claims

1. A method comprising the method steps of (i) initially charging at least one olefin, (ii) adding a complex comprising at least one diphenyl selenoxide of general structure (I) ##STR00012## where R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8 and R.sup.9 are each independently selected from the group consisting of H, (C.sub.1-C.sub.12)-alkyl and -halogen, where alkyl is linear, branched or cyclic, the alkyl groups optionally being substituted by at least one (C.sub.3-C.sub.12)-cycloalkyl group, and where R.sup.1 and R.sup.10 are each independently H, (C.sub.1-C.sub.12)-alkyl and/or halogen, where alkyl is linear, branched or cyclic, and at least one metal atom selected from the group consisting of Rh, Ru, Co and Ir or at least one diphenyl selenoxide of the general structure (I), as described above, and a substance having a metal atom selected from the group consisting of Rh, Ru, Co and Ir, (iii) feeding in H.sub.2 and CO, (iv) heating the reaction mixture, wherein the olefin is converted to an aldehyde.

Description

GENERAL METHODS

(1) Solvents and Reagents All reactions with moisture- and/or oxygen-sensitive, substances were carried out in baked-out apparatuses under an argon atmosphere. Solvents for extraction and column chromatography were used at the following purities: dichloromethane (99.9%, Walter, Cat. No. BlE 073107033), ethyl acetate (99.5%, Walter, Cat. No. BlE 003917025) and n-hexane (95%, Walter (Baked, Cat. No. 8669), n-heptane (95%, Walter (Baker), Cat. No. 8662). Other solvents for extraction and column chromatography were of technical quality and were used without further purification unless otherwise stated. Dry solvents (abs.) were purified using a Pure Solv MD-7 System and stored under an argon atmosphere. Benzyl bromide was freshly distilled (17 mbar/82 C.) prior to use. Deuterated solvents were distilled from the drying agents specified:

(2) dichloromethane-d.sub.2 (phosphorus pentoxide), toluene-d.sub.8 (1. KOH; 2. sodium). Chemicals used for the syntheses were supplied by Sigma Aldrich, Alfa Aesar, Acros Organics, Avantor Performance Materials B.V., Merck KGaA and ABCR GmbH & Co. KG. These were used without further purification unless otherwise stated.

(3) Chromatographic Methods

(4) Column chromatography Column chromatographic separations were carried out at elevated pressure (flash chromatography) on silica gel 60 230-400 mesh from Merck KGaA (particle size: 0.040-0.063 mm). The eluent mixtures used and the ratios by volume v/v are indicated in the specifications below. The following abbreviations apply to the eluents used: DCM (dichloromethane), EE (ethyl acetate). H (n-hexane) and Tel (toluene).

(5) Filtration: Filtrations for the removal of resulting solids were carried out using a G4 frit (pore width: 10-16 m).

(6) Analysis

(7) .sup.1H-NMR spectroscopy:.sup.1H-NMR spectra were recorded with a model AV 300 (300 MHz) and with the model Fourier 300 (300 MHz) from Bruker. Chemical shifts are stated in units on the -scale. The residual proton signals of the solvent (dichloromethane-d.sub.2: =5.32 ppm, toluene-d.sub.8:

(8) =7.09; 7.00; 6.98: 2.09 ppm) served as standard.

(9) .sup.13C-NMR spectroscopy:.sup.13C-NMR spectra were recorded with models AV 300 (75 MHz) and Fourier 300(75 MHz) from Bruker. The signal of the solvent (dichloromethane-d.sub.2: =54.0 ppm, toluene-d.sub.8:

(10) =137.9; 129.2; 128.3; 125.5; 20.4 ppm) served as internal standard wherein the chemical shifts were taken from the broadband .sup.1H-decoupled spectra.

(11) .sup.77Se-NMR spectroscopy:.sup.77Se-NMR spectra were recorded with an AV 300 (57 MHz) from Bruker. The spectra were measured in broadband .sup.1H-decoupled mode. The chemical shifts are reported in ppm.

(12) Mass spectrometry: EI mass spectra were recorded on a Finnigan MAT 95 XP instrument from Thermo Electron and ESI-TOF mass spectra with a model 6210 Time-of-Flight LC/MS from Agilent.

(13) Autoclave Experiments of Rhodium-Catalysed Hydroformylation

(14) The hydroformylation was conducted in a 200 ml autoclave equipped with pressure-retaining valve, gas flow meter, sparging stirrer and pressure pipette from Prernex Reactor AG, Lengau, Switzerland. The toluene used as solvent was purified using a Pure Solv MD-7 System and stored under argon. The substrate 1-octene or n-octene used as substrate (EVONIK Industries AG, octene isomeric mixture of 1-octene: 3.3%; cis+trans-2-octene: 48.5%;

(15) cis+trans-3-octene: 29.2%; cis+trans-octene-4: 16.4%; structurally isomeric octenes: 2.6%) was heated under reflux for several hours over sodium and distilled under argon.

(16) For the experiments, solutions of the catalyst precursor and the ligand were mixed in the autoclave under an argon atmosphere. [(acac)Rh(COD)] (Umicore, acac=acetylacetonate anion; COD=1,5-cyclooctadiene) was used as catalyst precursor. For experiments at a concentration of 100 ppm-m rhodium, 10 mL of a 4.31 mM solution were placed in the autoclave. Subsequently, the mass of ligand corresponding to a ratio L/Rh=5:1 (or 1:1) was dissolved and mixed in 10 mL of toluene. By adding further toluene, the starting volume of the catalyst solution was adjusted to 41.0 mL Into a pressure-resistant pipette was filled: 1-octene or n-octene (10.70 g). The autoclave was heated to the temperatures stated in each case at a total gas pressure (synthesis gas: Linde; H.sub.2(99.999%): CO (99.997%)=1:1) of a) 42 bar for a final pressure of 50 bar or b) 12 bar for a final pressure of 20 bar with stirring (1500 rpm). After reaching the reaction temperature, the synthesis gas pressure was increased to a) 48.5 bar for a final pressure of 50 bar or b) 19.5 bar for a final pressure of 20 bar and the reactant was introduced under a positive pressure of about 3 bar set in the pressure pipette. The reaction was conducted at a constant pressure of 50 or 20 bar (closed-loop pressure controller from Bronkhorst, the Netherlands) respectively over 4 h. After the reaction time had elapsed, the autoclave was cooled to room temperature, decompressed while stirring and purged with argon. 1.0 ml of each reaction mixture was removed immediately after the stirrer had been switched off, diluted with 5.0 ml of pentane and analysed by gas chromatography: HP 5890 Series II plus, PONA, 50m0.2mm0.5 m.

(17) Abbreviations: calc.=calculated; RT=room temperature

(18) The compound Ia (CAS 7304-91-8) is known from the literature. Ia was prepared according to: Canadian Journal of Chemistry, 88, 906-909, 2010.

(19) ##STR00009##

(20) Diphenyl selenides may also be prepared according to the European patent application ER15168377.8. Diphenyl selenides may be prepared by this method by reacting at least one first arene and optionally a second arene at a defined temperature in the presence of selenium dioxide in acids, in particular in the presence of an acid having a pKa in the range of 0-5. A preferred temperature range is from 50 to 120 C. The reaction time, i.e. the conversion, takes place preferably over a period of days. The arenes may be substituted by hydrogen, alkyl and/or halogen.

(21) Synthesis of diphenyl selenoxides I, in particular Ia. Analogously to the following synthetic procedure, the diphenyl selenoxides of the structure i may be prepared in accordance with the specified substituents.

(22) 175 L (234 mg, 1.00 mmol, 1.0 eq) of diphenyl selenide were reacted with 140 mg (1.05 mmol, 1.05 eq) of N-chlorosuccinimide. After extractive work-up, 235 mg (0.940 mmol, 94%) of the title compound I were obtained as a colourless solid.

(23) IR (ATR): (cm-1) =3044; 3008; 2989; 2941; 1570; 1470; 1437; 1300; 1156; 1069; 1056; 1047; 1017; 993; 915; 850; 820; 733; 686; 611; 481; 442, 1H-NMR (300 MHz, toluene-d8):

(24) (ppm)=7.67-7.51 (m, 4H, ArCH); 7.16-6.87 (m, 6H, ArCH); 13C -NMR (75 MHz, toluene-d8): (ppm)=145.1; 130.5; 129.3; 126.0; 77Se-NMR (57 MHz, toluene-d8): (ppm)=851.0; HR-MS (ESI-TOF): calc. for C12H11O Se ([M+H]+): 250.99700, found: 250.99691;

(25) calc. for C12H10OSeNa ([M+Na]+): 272.97894, found: 272.97888; C12H10OSe (249.99 g/mol). The analytical data are in agreement with the literature data.

(26) Bis(3,5-dimethyl-2-hydroxypheny)selenium

(27) ##STR00010##

(28) In a 250 mL round-bottom flask, 49.9 g of selenium dioxide (413 mmol) in 100 mL of pyridine were heated to 55 C. with the aid of an oil bath. 25 mL of 2,4-dimethylphenol (206 mmol) were then added and the temperature was maintained for seven and a half hours. On completion of the reaction, the mixture was diluted with 400 mL of ethyl acetate and filtered. The organic phase was washed with water and dried over magnesium sulphate, The pyridine was removed by distillation and the residue redissolved in ethyl acetate and washed with 10% hydrochloric acid and water in order to remove residues of pyridine. The organic phase was dried over magnesium sulphate and freed of the solvent under reduced pressure. The crude product thus obtained was heated under reflux in 400 mL of cyclohexane. After cooling to room temperature, the product crystallized. After one day, the product was filtered off, the filtrate was concentrated by half and again brought to crystallization at 4 C. This gave 18.56 g, 58 mmol (56%) of fine, pale yellow plates of the product

(29) m.sub.p=120.1 C. (recrystallization from cyclohexane)

(30) .sup.1H NMR (400 MHz, CDCl.sub.3) =7.11-7.12 (m, 2H), 6.90-6.92 (m, 2H), 5.95 (br, 2H, OH), 2.23 (s, 6H), 2.19 (s, 6H); .sup.13C NMR (100 MHz, CDCl.sub.3)=152.04, 133.35, 133.30, 130.67, 124.42, 115.31, 20.45, 16.69; .sup.77Se NMR (76 MHz, CDCl.sub.3) =164.91; HRMS for C.sub.16H.sub.18O.sub.2.sup.80 Se(ESI+)[M+Na.sup.+]: calculated: 345.0370; found: 445.0363;

(31) elemental analysis for C.sub.16H.sub.18O.sub.2Se: calculated: C: 59.82%, H: 5.65%; found: C: 59,69%, H: 5.76%.

(32) Catalysis-hydroformylation

(33) ##STR00011##

(34) TABLE-US-00001 TABLE 1 Presentation of the catalysis experiments using organoselenium compounds Olefin/ Rh/Ligand/ p T t Y S Entry Ligand solvent Olefin ratio [bar] [ C.] [h] [%] [%] 1 II n- 1:1:2197 50 120 4 9.5 33.2 octene/ (100 ppm toluene Rh) 3* Ia n- 1:1:2205 50 120 4 89.5 28.1 octene/ (40 ppm toluene Rh) Notes on Table 1: p = pressure, T = temperature, t = time, Y = yield; S = n-regioselectivity. *= inventive examples

(35) The rhodium-catalysed hydroformyiation using compound II (entry 2) led to a yield of 9.5% (obtained from 90.5% resdiual olefin) and an n-regioselectivity of 33.2%.

(36) The use of unprotected selenodiphenols II, i.e. those with two free OH groups, in the hydroformylation therefore leads to inhibition.

(37) By using the diphenyl selenoxide Ia, a high yield of 89.5% in the hydroformylation with n-octene could be recorded.

(38) Catalysis experiments 2) and 3) illustrate the successful use of diphenyl selenoxide in rhodium-catalysed hydroformylation. The object was therefore met.