Selective reduction of esters to alcohols

Abstract

The present invention relates to a selective reduction of esters to their corresponding alcohols.

Claims

1. A process of production of a compound of formula (II): ##STR00040## wherein R.sub.1 is an aromatic ring system which is unsubstituted or an aromatic ring system which is substituted; a heteroaromatic ring system which is unsubstituted or a heteroaromatic ring system which is substituted; an aliphatic ring system which is unsubstituted or an aliphatic ring system which is substituted; CH.sub.3; CH.sub.2CH.sub.3; an unsubstituted C.sub.3-C.sub.22 alkyl group, which can be linear or branched and which can also be partially unsaturated; or a substituted C.sub.2-C.sub.22 alkyl group, which can be linear or branched and which can also be partially unsaturated, wherein the process comprises conducting a selective reduction of a compound of formula (I): ##STR00041## wherein R is a linear C.sub.1-C.sub.6-alkyl group, which can be substituted; a branched C.sub.3-C.sub.6-alkyl group, which can be substituted or a benzyl group, which can be substituted, and R.sub.1 is an aromatic ring system which is unsubstituted or an aromatic ring system which is substituted; a heteroaromatic ring system which is unsubstituted or a heteroaromatic ring system which is substituted; an aliphatic ring system which is unsubstituted or an aliphatic ring system which is substituted; CH.sub.3; CH.sub.2CH.sub.3; an unsubstituted C.sub.3-C.sub.22 alkyl group, which can be linear or branched and which can also be partially unsaturated; or a substituted C.sub.2-C.sub.22 alkyl group, which can be linear or branched and which can also be partially unsaturated, or R and R.sub.1 form together a 4 to 7 membered ring system, which can be substituted, and wherein the selective reduction is carried out in the presence of at least one transition metal catalyst of formula (III):
[M(L)(X).sub.a(L).sub.b](III), wherein M is a transition metal and X is an anion, and L is a monodentate ligand, and L is a tridentate ligand of formula (IV): ##STR00042## wherein R.sub.3 is a linear C.sub.1-C.sub.4 alkyl group, which can be substituted; a branched C.sub.3-C.sub.4 alkyl group, which can be substituted; or a phenyl group, which can be substituted, R.sub.4 is H; a linear C.sub.1-C.sub.4 alkyl group, which can be substituted; a branched C.sub.3-C.sub.4 alkyl group, which can be substituted; or OC.sub.1-C.sub.2alkyl, R.sub.5 is H; a linear C.sub.1-C.sub.4 alkyl group, which can be substituted; a branched C.sub.3-C.sub.4 alkyl group, which can be substituted; or OC.sub.1-C.sub.2alkyl, or R.sub.4 and R.sub.5 form a C.sub.4-C.sub.8 ring system, which can be aliphatic or aromatic, and R.sub.6 is H; a linear C.sub.1-C.sub.4 alkyl group, which can be substituted; a branched C.sub.3-C.sub.4 alkyl group, which can be substituted; or OC.sub.1-C.sub.2alkyl, R.sub.7 is H; a linear C.sub.1-C.sub.4 alkyl group, which can be substituted; a branched C.sub.3-C.sub.4 alkyl group, which can be substituted; or OC.sub.1-C.sub.2alkyl, R.sub.8 is H or a linear C.sub.1-C.sub.4 alkyl group, which can be substituted; a branched C.sub.3-C.sub.4 alkyl group, which can be substituted, R.sub.9 is CH.sub.3 or CH.sub.2CH.sub.3, m is 0, 1 or 2, and n is 0, 1 or 2, with the proviso that the sum of m+n is 1 or 2, o is 2 or 3, a is 0, 1, 2, or 3, and b is 0, 1, 2, or 3, with the proviso that the sum of a+b is 2, 3 or 4.

2. The process according to claim 1, wherein the process is carried out in the presence of at least one base.

3. The process according to claim 1, wherein the process is carried out in the presence of at least one base of formula (VIII):
M.sup.1(OC.sub.1-C.sub.5alkyl)(VIII), wherein M.sup.1 is an alkali metal.

4. The process according to claim 1, wherein the process is carried out in the presence of at least one base of formula (VIII):
M.sup.1(OC.sub.3-C.sub.5alkyl)(VIII) wherein M.sup.1 is Li, Na or K.

5. The process according to claim 1, wherein the process is carried out in the presence of at least one base selected form the group consisting of KOtBu, NaOtBu and LiOtBu.

6. The process according to claim 1, wherein the catalyst is a compound of formula (III):
[M(L)(X).sub.a(L).sub.b](III), wherein M is a transition metal selected from the group consisting of Os, Co, Ru and Fe, and X is a halogen anion, a carboxylate, borohydride, hydride, BF.sub.4.sup. or PF.sub.6.sup., and L is a monodentate phosphine ligand, and L is a tridentate ligand of formula (IV): ##STR00043## wherein R.sub.3 is CH.sub.3 or CH.sub.2CH.sub.3, R.sub.4 is H; CH.sub.3; CH.sub.2CH.sub.3; OCH.sub.3 or OCH.sub.2CH.sub.3, and R.sub.5 is H; CH.sub.3; CH.sub.2CH.sub.3; OCH.sub.3 or OCH.sub.2CH.sub.3, or R.sub.4 and R.sub.5 form a C.sub.4-C.sub.8 ring system, which can be aliphatic or aromatic, and R.sub.6 is H; CH.sub.3; CH.sub.2CH.sub.3; OCH.sub.3 or OCH.sub.2CH.sub.3, R.sub.7 is H; CH.sub.3; CH.sub.2CH.sub.3; OCH.sub.3 or OCH.sub.2CH.sub.3, R.sub.8 is H; CH.sub.3 or CH.sub.2CH.sub.3, R.sub.9 is CH.sub.3 or CH.sub.2CH.sub.3, m is 0, 1 or 2, and n is 0, 1 or 2, with the proviso that the sum of m+n is 1 or 2, o is 2 or 3, a is 0, 1, 2, or 3, and b is 0, 1, 2, or 3, with the proviso that the sum of a+b is 2 or 3.

7. The process according to claim 1, wherein the catalyst is a compound following catalysts of formula (III):
M(L)(X).sub.2(L)(III), wherein M is Ru or Fe, X is Cl.sup., L is PPh.sub.3, and L is a tridentate ligand selected from the group consisting of the ligands of formulae (IVa)-(IVl): ##STR00044##

8. The process according to claim 1, wherein the catalyst of formula (III) is used in an amount of 0.001-0.5 mol-%, based on the number of moles of the compounds of formula (I).

9. The process according to claim 1, wherein the reduction is a transfer hydrogenation.

10. The process according to claim 1, wherein the process is carried out with H.sub.2 gas.

11. The process according to claim 10, wherein the process is carried out at a pressure of 10-50 bar.

12. The process according to claim 1, wherein the process is carried out at a temperature of 30-150 C.

Description

EXAMPLES

(1) General:

(2) Transition metal precursors, reagent and solvents were obtained from commercial sources and used as received unless noted otherwise. GC analysis was carried out on an Agilent 7890B GC system with a HP-5 normal-phase silica column, using Helium as a carrier gas and dodecane as an internal standard. NMR spectra were recorded on a Bruker AV400, Bruker AV300 or Bruker Fourier300 NMR spectrometer. .sup.1H and .sup.13C-NMR spectra were referenced w.r.t. the solvent signal. Chemical shifts are in ppm, coupling constants in Hz. HR-MS measurements were recorded on an Agilent 6210 Time-of-Flight LC/MS, peaks as listed correspond to the highest abundant peak and are of the expected isotope pattern.

Ligand Synthesis

Example 1: 2-(ethylthio)-N-((6-methylpyridin-2-yl)methyl)ethan-1-amine [Ligand of Formula (IVg)]

(3) ##STR00025##

(4) 6-methylpyridine-2-carboxaldehyde (3.0 g, 25 mmol) and 2-(Ethylthio)ethylamine (2.63 g, 2.8 mL, 25 mmol) were dissolved in CH.sub.2Cl.sub.2 (75 mL), then Na.sub.2SO.sub.4 (7.1 g, 50 mmol) was added. The suspension was stirred at room temperature overnight, filtered and the filter cake was washed with CH.sub.2Cl.sub.2. The combined volatiles were removed in vacuo, yielding 5.45 g of imine as brown oil, which was used directly in the following step without further purification. Therefore, the imine was dissolved in MeOH (50 mL) and NaBH.sub.4 (1.9 g, 51 mmol) was added portionwise at 0 C. The mixture was stirred at room temperature for another hour, after which the solvent was removed in vacuo. Then CH.sub.2Cl.sub.2 (20 mL) and water (20 mL) were added. The aqueous layer was extracted with CH.sub.2Cl.sub.2 (three times 20 mL). The combined organic layers were washed with brine (20 mL) and dried over Na.sub.2SO.sub.4. Evaporating the solvent and drying in vacuo yielded 4.95 g (94%) of the ligand of formula (IVg) as an orange oil, which was directly used for complex synthesis.

(5) .sup.1H-NMR (300 MHz, CDCl.sub.3): 7.45 (t, 1H, J=7.6, CH.sub.arom), 7.07 (d, 1H, J=7.8, CH.sub.arom), 6.96 (d, 1H, J=7.5, CH.sub.arom), 3.84 (s, 2H), 2.80 (dt, 2H), 2.66 (dt, 2H), 2.48 (m, 5H), 1.23 (t, 3H, J=7.4) ppm.

(6) .sup.13C-NMR (75 MHz, CDCl.sub.3): 158.9, 157.8, 136.5, 121.3, 118.9, 54.9, 48.2, 31.8, 25.6, 24.4 ppm.

(7) HRMS (ESI+): calculated for C.sub.11H.sub.18N.sub.2S: 210.1191; found 211.1265 (M+H), 233.1082 (M+Na).

Example 2: 2-(methylthio)-N-((pyridin-2-yl)methyl)ethan-1-amine [Ligand of Formula (IVa)]

(8) ##STR00026##

(9) The ligand of formula (IVa) was prepared in analogy to Example 1.

(10) .sup.1H NMR (300 MHz, CD.sub.2Cl.sub.2) 8.43 (ddd, 1H, J=4.9 Hz, J=1.8 Hz, J=0.9 Hz, CH.sub.arom), 7.57 (td, 1H, J=7.7 Hz, J=1.8 Hz, CH.sub.arom), 7.24 (d, 1H, J=7.8 Hz, CH.sub.arom), 7.07 (dd, 1H, J=7.5 Hz, J=5.0.7 Hz, CH.sub.arom), 3.81 (s, 2H), 2.75 (td, 2H, J=6.5 Hz, J=0.8 Hz, CH.sub.2), 2.58 (td, 2H, J=6.5 Hz, J=0.6 Hz, CH.sub.2), 1.99 (s, 3H, CH.sub.3) ppm.

(11) .sup.13C NMR (75 MHz, CD.sub.2Cl.sub.2): 160.2, 149.1, 136.2, 121.9, 121.7, 54.8, 47.6, 34.4, 15.0 ppm.

(12) HRMS (ESI+): calculated for C.sub.9H.sub.14N.sub.2S: 182.0878 (M+H): 183.0950; found 183.0950 (M+H).

Example 3: 2-(ethylthio)-N-((pyridin-2-yl)methyl)ethan-1-amine [Ligand of Formula (IVb)]

(13) ##STR00027##

(14) The ligand of formula (IVb) was prepared according to Example 1.

(15) .sup.1H NMR (300 MHz, CD.sub.2Cl.sub.2): 8.51 (ddd, 1H, J=4.8 Hz, J=1.5 Hz, J=0.9 Hz, CH.sub.arom), 7.64 (td, 1H, J=7.5 Hz, J=1.8 Hz, CH.sub.arom), 7.32 (d, 1H, J=7.8 Hz, CH.sub.arom), 7.19-7.12 (m, 1H, CH.sub.arom), 3.88 (s, 2H, CH.sub.2), 2.85-2.79 (m, 2H, CH.sub.2), 2.72-2.66 (m, 2H, CH.sub.2), 2.52 (q, 2H, J=7.5 Hz, CH.sub.2), 2.09 (d, 1H, J=9.6 Hz, NH), 1.23 (t, 3H, J=7.4 Hz, CH.sub.3) ppm.

(16) .sup.13C NMR (75 MHz, CD.sub.2Cl.sub.2): 161.6, 149.7, 136.8, 122.5, 122.3, 55.4, 48.9, 32.5, 26.2, 15.3 ppm.

(17) HRMS (ESI+): calculated for C.sub.10H.sub.16N.sub.2S: 196.1034; (M+H): 197.1107; (M+Na): 219.0926; found 197.1108 (M+H), 219.0929 (M+Na).

Example 4: 2-(ethylthio)-N-((6-methoxy-pyridin-2-yl)methyl)ethan-1-amine [Ligand of Formula (IVk)]

(18) ##STR00028##

(19) The ligand of formula (IVk) was prepared according to Example 1 in a 84% yield.

(20) .sup.1H-NMR (300 MHz, CDCl.sub.3): 7.54 (dd, 1H, J=8.1, J=7.4, CH.sub.arom), 6.87 (d, 1H, J=7.2), 6.63 (d, 1H, J=8.1), 4.55 (s, NH), 3.92 (s, 3H), 3.90 (m, NH), 3.80 (s, 2H), 2.83 (t, 2H, J=6.5), 2.66 (t, 2H, J=6.5), 2.52 (t, 2H, J=7.5), 1.23 (t, 3H, J=7.2) ppm. .sup.13C-NMR (75 MHz, CDCl.sub.3): 163.8, 157.3, 138.8, 114.5, 108.7, 54.3, 53.2, 48.1, 32.0, 25.8, 14.8 ppm.

(21) HRMS (ESI+): calculated for C.sub.11H.sub.18N.sub.2OS: 227.1213 (M+H); found 227.1217 (M+H).

Example 5: 2-(ethylthio)-N-((quinolin-2-yl)methyl)ethan-1-amine [Ligand or Formula (IVl)]

(22) ##STR00029##

(23) The ligand of formula (IVl) was prepared according to Example 1 and purification by Kugelrohr distillation.

(24) .sup.1H NMR (300 MHz, CD.sub.2Cl.sub.2): 8.13 (d, 1H, J=8.4 Hz, CH.sub.arom), 8.00 (d, 1H, J=8.7 Hz, CH.sub.arom), 7.82 (dd, 1H, J=8.3 Hz, J=1.5 Hz, CH.sub.arom), 7.69 (ddd, 3H, J=8.5 Hz, J=6.9 Hz, J=1.5 Hz, CH.sub.arom), 7.55-7.45 (m, 2H, CH.sub.arom), 4.08 (s, 2H, CH.sub.2), 2.89 (td, 2H, J=6.8 Hz, J=1.2 Hz, CH.sub.2), 2.73 (td, 2H, J=6.4 Hz, J=0.9 Hz, CH.sub.2), 2.55 (q, 2H, J=7.4 Hz, CH.sub.2), 2.14 (d, 1H, J=11.4 Hz, NH), 1.24 (t, 3H, J=7.4 Hz, CH.sub.3) ppm.

(25) .sup.13C NMR (75 MHz, CD.sub.2Cl.sub.2): 161.5, 136.7, 129.8, 129.5, 128.1, 127.9, 126.5, 121.0, 56.0, 49.1, 32.6, 26.2, 15.29 ppm.

(26) HRMS (ESI+): calculated for C.sub.14H.sub.18N.sub.2S: 246.1191; (M+H): 247.1264; found 247.1267 (M+H).

Example 6: 2-(ethylthio)-N-(1-(pyridin-2-yl)ethyl)ethan-1-amine [Ligand or Formula (IVe)]

(27) ##STR00030##

(28) The ligand of formula (IVe) was prepared according to Example 1 with imine formation performed in the presence of 5 mol % of p-toluenesulfonic acid in toluene under reflux conditions and purification by Kugelrohr distillation.

(29) .sup.1H NMR (300 MHz, CD.sub.2Cl.sub.2): 8.51 (ddd, 1H, J=4.8 Hz, J=1.9 Hz, J=1.0 Hz, CH.sub.arom), 7.64 (td, 1H, J=7.6 Hz, J=1.8 Hz, CH.sub.arom), 7.32 (dt, 1H, J=7.8 Hz, J=1.1 Hz, CH.sub.arom), 7.14 (ddt, 1H, J=7.5 Hz, J=4.8 Hz, J=1.2 Hz, CH.sub.arom), 3.84 (q, 1H, J=6.9 Hz, CH), 2.71-2.55 (m, 4H, CH.sub.2), 2.47 (q, 2H, J=7.4 Hz, CH.sub.2), 2.05 (d, 1H, J=39.3 Hz, NH), 1.34 (d, 3H, J=6.9 Hz, CH.sub.3), 1.20 (d, 3H, J=7.5 Hz, CH.sub.3) ppm.

(30) .sup.13C NMR (75 MHz, CD.sub.2Cl.sub.2): 165.4, 149.7, 136.9, 122.3, 121.4, 59.7, 47.1, 32.7, 26.1, 23.2, 15.2 ppm.

(31) HRMS (ESI+): calculated for C.sub.11H.sub.18N.sub.2S: 210.1191; (M+H), 211.1264; (M+Na): 233.1083; found 211.1265 (M+H), 233.1083 (M+Na).

Example 7: 2-(ethylthio)-N-methyl-N-(pyridin-2-ylmethyl)ethan-1-amine [Ligand or Formula (IVd)]

(32) ##STR00031##

(33) 2-(Ethylthio)-N-(pyridin-2-ylmethyl)ethan-1-amine (ligand of formula (IVb), 850 mg, 3.75 mmol), formalin (4 mL of 37% wt formaldehyde in water) and formic acid (4 mL) were stirred at 70 C. overnight. All volatiles were removed in vacuo and CH.sub.2Cl.sub.2 (10 mL) and saturated NaHCO.sub.3 solution (10 mL) were added. The aqueous layer was extracted with CH.sub.2Cl.sub.2 (three times 10 mL). The combined organic layers were washed with brine (20 mL) and dried over Na.sub.2SO.sub.4. Removal of the solvent yielded 754 mg (3.59 mmol, 96%) of 2-(ethylthio)-N-methyl-N-(pyridin-2-ylmethyl)ethan-1-amine as an orange liquid (p=1.081 g cm.sup.3). The ligand of formula (IVb) was further purified by Kugelrohr distillation.

(34) .sup.1H-NMR (300 MHz, CDCl.sub.3): 8.46 (d, 1H, J=5.1, CH.sub.arom), 7.58 (dt, 1H, J=7.8, J=1.8, CH.sub.arom), 7.38 (d, 1H, J=7.8, CH.sub.arom), 7.08 (ddd, 1H, J=7.5, J=4.8, J=1.2, CH.sub.arom), 3.62 (s, 2H), 2.62 (s, 4H), 2.45 (q, 2H, J=7.4), 2.31 (s, 3H, NCH.sub.3), 1.17 (t, 3H, J=7.4) ppm.

(35) .sup.13C NMR (101 MHz, CDCl.sub.3): 159.2, 149.0, 136.4, 123.1, 122.0, 63.6, 57.3, 56.9, 42.4, 31.9, 29.3, 26.1, 14.8 ppm.

(36) HRMS (ESI+): calculated for C.sub.11H.sub.18N.sub.2S: 210.1191; found 211.1265 (M+H), 233.1084 (M+Na).

Catalyst Synthesis

Example 8: Ru(6-MeNNSEt)(PPh3)Cl2

(37) ##STR00032##

(38) RuCl.sub.2(PPh.sub.3).sub.3 (1 g, 1.04 mmol) and the ligand of formula (IVg) (obtained from Example 1) (231.4 mg, 1.1 mmol) were placed in a 25 mL Schlenk tube under argon atmosphere, and dissolved in dry diglyme (2 mL). The reaction mixture was heated to 165 C. for 2 h, allowed to cool down to room temperature and stored at 18 C. to precipitate further overnight. Cold Et.sub.2O (2 mL) was added while cooling with a dry ice/iso-propanol bath. The precipitate was filtrated by cannula, and washed with Et.sub.2O (5 times 2 mL). The orange powder was dried in vacuo, affording 530 mg (79%) of Ru(6-MeNNS.sup.Et)(PPh.sub.3)Cl.sub.2 as an orange powder. An equilibrium of two conformations of Ru(6-MeNNS.sup.Et)(PPh.sub.3)Cl.sub.2 are existent in solution, delivering a doubled set of signals in NMR. For .sup.1H-NMR only data of the major conformation is given due to overlapping signals.

(39) .sup.1H-NMR (300 MHz, CD.sub.2Cl.sub.2): 7.67-7.16 (m, 17H, CH.sub.arom), 7.01 (d, 1H, J=7.8, CH.sub.arom), 5.65 (m, 2H), 4.47 (m, 1H), 3.5 (m, 1H), 3.34 (m, 1H), 3.22 (d, 1H, J=11.1), 2.98 (m, 1H), 2.59 (m, 1H), 1.53 (m, 2H), 0.87 (t, 3H, J=7.5) ppm.

(40) .sup.31P-NMR (122 MHz, CD.sub.2Cl.sub.2): 48.8, 45.8 ppm.

(41) HRMS (ESI+): calculated for C.sub.29H.sub.32Cl.sub.2N.sub.2PRuS (M+H): 644.0518; found 644.0518 (M+H), 667.0412 (M+Na).

Example 9: Ru(NNSMe)(PPh3)Cl2

(42) ##STR00033##

(43) Ru(NNS.sup.Me)(PPh.sub.3)Cl.sub.2 was prepared according to Example 8. An equilibrium of two conformations was obtained.

(44) .sup.1H-NMR (300 MHz, CD.sub.2Cl.sub.2): 8.47 (d, 1H, J=5.7), 7.72 (m, 1H), 7.56 (m, 6H), 7.32 (m, 10H), 6.86 (t, 1H, J=6.3), 5.45 (s, broad, 1H, NH), 5.20 (t, 1H, J=12.6), 4.38 (m, 1H), 3.41 (m, 2H), 3.26 (d, 1H, J=11.1), 2.55 (m, 1H), 1.50 (s, 3H).

(45) .sup.31P-NMR (122 MHz, CD.sub.2Cl.sub.2): 51.8, 50.7

(46) HRMS (ESI+): calculated for C.sub.27H.sub.29Cl.sub.2N.sub.2PRuS: 616.0210 (M+); found 616.0197 (M+).

Example 10: Ru(NNSEt)(PPh3)Cl2

(47) ##STR00034##

(48) Ru(NNS.sup.Et)(PPh.sub.3)Cl.sub.2 was prepared according to Example 8. An equilibrium of two conformations was obtained in 84% yield.

(49) .sup.1H-NMR (300 MHz, CD.sub.2Cl.sub.2): 8.45 (d, 1H, J=5.7), 7.72 (m, 1H), 7.57 (m, 6H), 7.34 (m, 10H), 6.86 (t, 1H, J=6.3), 5.49 (s, broad, 1H, NH), 5.22 (t, 1H, J=13.5), 4.40 (m, 1H), 3.47 (m, 2H), 3.36 (m, 1H), 2.80 (m, 1H), 2.52 (m, 1H), 1.27 (m, 2H), 1.19 (m, 1H), 0.95 (t, 3H, J=7.5)

(50) .sup.31P-NMR (122 MHz, CD.sub.2Cl.sub.2): 51.8, 50.7

(51) HRMS (ESI+): calculated for C.sub.28H.sub.31Cl.sub.2N.sub.2PRuS: 630.0366 (M+); found 630.0388 (M+), 653.0270 (M+Na).

Example 11: Ru(6-MeONNSEt)(PPh3)Cl2

(52) ##STR00035##

(53) Ru(6-MeONNS.sup.Et)(PPh.sub.3)Cl.sub.2 was prepared according to Example 8. An equilibrium of two conformations was obtained in 88% yield.

(54) .sup.1H-NMR (400 MHz, CD.sub.2Cl.sub.2): 7.94 (m, 2H), 7.65 (m, 2H), 7.42-7.14 (m, 12H), 7.07 (d, 1H, J=7.6), 6.56 (d, 1H, J=8.4), 5.56-5.36 (m, 2H), 4.46 (m, 1H), 3.50-3.19 (m, 2H), 3.21 (dd, 1H, J=11.0, J=2.2), 2.87 (m, 1H), 2.83 (s, 3H, twinned), 2.50 (m, 1H), 1.33 (m, 1H), 0.87 (t, 3H, twinned, overlapping)

(55) .sup.31P-NMR (122 MHz, CD.sub.2Cl.sub.2): 47.2, 45.9

(56) HRMS (ESI+): calculated for C.sub.29H.sub.32Cl.sub.2N.sub.2OPRuS (M+H): 660.0468; found: 660.0469 (M+H), 683.0363 (M+Na).

Example 12: Ru(QuinNSEt)(PPh3)Cl2

(57) ##STR00036##

(58) Ru(QuinNS.sup.Et)(PPh.sub.3)Cl.sub.2 was prepared according to Example 8. An equilibrium of two conformations was obtained.

(59) .sup.1H-NMR (300 MHz, CD.sub.2Cl.sub.2): 8.12 (d, 2H, J=8.4), 7.74-6.66 (m, 19H), 5.90 (s, broad, NH), 5.74 (t, 1H, J=13.3), 4.72 (m, 1H), 3.58-3.40 (m, 3H), 3.05 (m, 1H), 2.72 (m, 1H), 1.66 (m, 1H), 0.95 (t, 3H, J=7.5)

(60) .sup.31P NMR (122 MHz, CD.sub.2Cl.sub.2): 48.90, 45.86

(61) HRMS (ESI+): calcd. for C.sub.32H.sub.33Cl.sub.2N.sub.2PRuS: 680.0519 (M+); found 680.0500 (M+).

Example 13: Ru(N-Me-NSEt)(PPh3)Cl2

(62) ##STR00037##

(63) Ru(N-Me-NS.sup.Et)(PPh.sub.3)Cl.sub.2 was prepared according to Example 8. An equilibrium of two conformations was obtained.

(64) .sup.1H-NMR (300 MHz, CD.sub.2Cl.sub.2): 8.53 (d, 1H, J=5.7), 7.72 (m, 1H), 7.57 (m, 6H), 7.33 (m, 10H), 6.85 (t, 1H, J=6.6), 5.35 (m, 1H), 4.93 (s, broad, NH), 3.68-3.31 (m, 3H), 2.81 (m, 1H), 2.53 (m, 1H), 1.80 (d, 3H, J=6.9), 1.25 (m, 1H), 0.97 (t, 3H, J=7.2) .sup.31P NMR (122 MHz, CD.sub.2Cl.sub.2): 51.5, 50.3

(65) HRMS (ESI+): calculated for C.sub.29H.sub.33Cl.sub.2N.sub.2PRuS: 644.0518 (M+); found 644.0513 (M+).

Example 14: Ru(NNMeSEt)(PPh3)Cl2

(66) ##STR00038##

(67) Ru(NN.sup.MeS.sup.Et)(PPh.sub.3)Cl.sub.2 was prepared according to Example 8. An equilibrium of two conformations was obtained in 54%.

(68) .sup.1H-NMR (300 MHz, CD.sub.2Cl.sub.2): 8.11 (d, 1H, J=5.7), 7.92 (m, 6H), 7.47 (dt, 1H, J=7.5, J=1.5), 7.30 (m, 10H), 6.56 (t, 1H, J=7.5), 5.67 (d, 1H, J=14.4), 3.87 (d, 1H, J=14.4), 3.15 (s, 3H), 2.86 (m, 1H), 2.70 (m, 1H), 2.30 (m, 2H), 0.74 (m, 1H), 0.67 (t, 3H, J=6.9), 0.42 (m, 1H)

(69) .sup.31P-NMR (122 MHz, CD.sub.2Cl.sub.2): 51.4, 50.4

(70) HRMS (ESI+): calculated for C.sub.29H.sub.33Cl.sub.2N.sub.2PRuS: 644.0518 (M+); found 644.0505 (M+).

Hydrogenation Reactions

Example 15: Selective Hydrogenation of a Specific Ester

(71) The compounds of formulae (A) were hydrogenated.

(72) ##STR00039##

(73) 4 mL glass reaction vials and stirring bars were dried overnight at 110 C., closed with PTFE/rubber septa, placed in a multiple reactor inlet suitable for a pressure vessel, and brought under argon atmosphere by three vacuum-argon cycles. With a syringe the reaction vessels were charged with the catalyst as stock solution in iPrOH (1 mL, 0.0005 mol/L, 0.05 mol %), followed by a solution of the compound A, in iPrOH (1 mL, 1 mol/L, 1 mmol). After that a solution of freshly sublimed base in THF (12.5 L, 1 mol/L, 0.0125 mmol, 1.25 mol %) was added with a syringe. The reaction mixtures were transferred to an argon-filled pressure vessel, which was immediately flushed with three nitrogen and three hydrogen cycles, then pressurized to 30 bar hydrogen, heated to 80 C. and stirred for 16 h. After that the pressure vessel was cooled down to room temperature and depressurized. The reaction mixtures were filtered over silica and rinsed with ethanol (2 mL). The products are determined based on GC analysis retention time. The given values [%] are related to GC area %.

(74) The results are summarized in the following table.

(75) TABLE-US-00001 TABLE 1 HYDROGENATION OF THE COMPOUND OF FORMULA (A) Product Cat. Base Conversion Compound A Exp. 0.05 mol % 1-2 mol % C [%] Y [%] S [%] 15a Cat of Exp. 9 KOtBu 100 100 100 15b Cat of Exp. 10 KOtBu 100 99 99 15c Cat of Exp. 10 LiOtBu 100 99 99

Example 16

(76) In a similar manner as described in Example 15 methyl hexanoate was hydrogenated to 1-hexanol. In this experiment the catalyst of Exp 9 was used and NaOtBu was used as base. The ratios between substrate base and catalyst were 262:29:1. The temperature was 100 C. and the hydrogen pressure 30 bar. After 16 h the solution was analysed and 1-hexanol was found in 43% yield.

Example 17

(77) A 100 mL hastelloy autoclave with mechanical stirrer was charged with the catalyst of example 9 (3.3 mg, 0.005 mmol), methyl stearate (2.98 g, 10 mmol), 20 mL of toluene, and freshly sublimed KOtBu (7 mg, 0.0625 mmol, 1.25 mol %) under an argon atmosphere. The autoclave vessel was then pressurized to 30 bar hydrogen, heated to 100 C. and stirred for 16 hours. The pressure vessel was cooled down to room temperature and depressurized. Removal of the solvent in vacuo yielded 2.7 g of stearyl alcohol as an off-white flaky powder.

(78) 1H NMR (300 MHz, CDCl3): 3.69 (dt, 2H, J=6.6; J=5.4 Hz), 1.62 (m, 2H), 1.30 (m, 31H), 0.93 (t, 3H, J=6.3 Hz) ppm.

(79) GC-MS (ESI): single component, calculated for C18H38O: 270 (M); found 269 (MH).

Example 18: Hydrogenation of Cinnamate Esters

(80) A 100 mL hastelloy autoclave with mechanical stirrer was charged with the catalyst of example 9 (23 mg, 0.038 mmol, 0.25 mol %), substrate (15 mmol), 30 mL of toluene, freshly sublimed KOtBu (41 mg, 0.38 mmol, 2.5 mol %), and 1000 l of anhydrous n-dodecane under an argon atmosphere. The autoclave vessel was flushed with nitrogen three times, and with hydrogen two times, then pressurized to 30 bar H2, heated to 40 C. and stirred for 4 hours. During the reaction time the pressure was kept at 30 bar H.sub.2. The products are determined based on GC analysis retention time. The given values for conversion (C), yield (Y), and selectivity (S) [%] are mol % with regard to the initial cinnamyl ester amount, and corrected by n-dodecane. The results are summarized in the following table.

(81) TABLE-US-00002 TABLE 2 hydrogenation of cinnamate esters Exp Substrate T [ C.] t [h] C [%] S [%] Y [%] 18a Methyl cinnamate 40 4 >99 90 90 18b Isobutyl cinnamate 40 4 >99 95 95

Example 19: Hydrogenation of 5-methyldihydrofuran-2(3H)-one

(82) The catalyst of example 9 (23 mg, 0.038 mmol, 0.25 mol %), 5-methyldihydrofuran-2(3H)-one (1.46 g, 15 mmol), 30 mL of toluene, and freshly sublimed KOtBu (41 mg, 0.38 mmol, 2.5 mol %) were reacted according to the method in Example 18. An amount of 25 mL of the reaction mixture was used for the product purification. Column chromatography yielded 1.399 g (92%) of pentane-1,4-diol.

Example 20: Hydrogenation of methyl cyclohex-1-ene-1-carboxylate

(83) Methyl cyclohex-1-ene-1-carboxylate was hydrogenated according to Example 18. The reaction mixture was initially heated to 60 C. After stirring for 1 hour the vessel was allowed to cool down to 40 C. and was kept at this temperature under stirring for 5 hours. Column chromatography yielded 0.75 g (63%) of cyclohex-1-en-1-ylmethanol.