Hydrogenation of imines with Ru complexes

Patent metadata

Field	Value
Publication number	US-11498901-B2
Application number	US-201916766556-A
Country	US
Kind code	B2
Filing date	Feb 18, 2019
Priority date	Mar 2, 2018
Publication date	Nov 15, 2022
Grant date	Nov 15, 2022

Abstract

Described herein are catalytic hydrogenation and the use of ruthenium complexes having a bidentate diphosphine ligand or two monodentate phosphine ligands, two carboxylate ligands, and optionally a diamine ligand in hydrogenation processes for the reduction of imines into the corresponding amines.

First claim

The invention claimed is:

1. A process for the reduction by hydrogenation, using molecular H 2 , of a C 5 -C 20 substrate of formula

wherein R a and R c represent, independently from each other, a hydrogen atom or a C 1 -C 15 hydrocarbon group optionally comprising one to three oxygen atoms and/or one to two nitrogen atoms and/or one sulphur or halogen atom; R b represents a C 1 -C 15 hydrocarbon group optionally comprising one to three oxygen atoms and/or one to two nitrogen atoms and/or one sulphur or halogen atom, a hydrogen atom, a SO 2 R b′ , a OR b″ or a POR b′ 2 group wherein R b′ represents a C 1 -C 6 alkyl group or a phenyl or tolyl group and R b′ represents a hydrogen atom, a C 1 -C 6 alkyl group or a phenyl or tolyl group; or R a and R c represent, when taken together, a C 1 -C 10 alkanediyl or alkenediyl group; provided that at least one R a , R b , or R c is not a hydrogen atom;
into the corresponding amine, wherein said process is carried out in the presence of at least one catalyst or pre-catalyst of formula
[Ru(PP)(NN) n (RCOO) 2 ](1) or [Ru(P) 2 (NN) n (RCOO) 2 ]  (1′)

wherein n is 0 or 1;
PP represents a C 5 -C 50 bidentate ligand wherein the coordinating groups are two phosphino groups;
P represents a C 3 -C 50 monodentate ligand;
NN represents a C 2 -C 20 bidentate ligand wherein the coordinating atoms are two nitrogen atoms; and
each R represents, simultaneously or independently, a hydrogen atom, a C 1 -C 12 linear hydrocarbon group, or a branched or cyclic C 3 -C 12 hydrocarbon group and said hydrocarbon group comprises optionally one to five heteroatoms selected amongst halogen, oxygen and nitrogen atoms; and
wherein the process is performed in the absence of a base additive.

2. The process according to claim 1 , wherein R a , R b and R c represent, independently from each other, a hydrogen atom, a C 1 -C 10 linear alkyl group, a C 2 -C 10 linear alkenyl group, a C 3 -C 10 linear, branched, or cyclic alkyl or alkenyl group, a C 4 -C 10 linear, branched, or cyclic alkadienyl group, a C 3-8 aryl, a C 2-8 heterocyclic, or a C 6-12 arylalkyl group optionally substituted by a hydroxyl group, a C 1-6 alkyl group or a C 1-6 alkoxy group; or R a and R c represent, when taken together, a C 1 -C 10 alkanediyl or alkenediyl group; provided that at least one R a , R b , or R c is not a hydrogen atom.

3. The process according to claim 1 , wherein R c is a hydrogen atom.

4. The process according to claim 1 , wherein R a or R b represent a C 2-6 heterocyclic group optionally substituted by a hydroxyl group, a C 1-3 alkyl group, or a C 1-3 alkoxy group and the other represents a C 1 -C 8 linear alkyl group, a C 2 -C 8 linear alkenyl group, a C 3 -C 8 linear, branched, or cyclic alkyl or alkenyl group, a C 4 -C 8 linear, branched, or cyclic alkadienyl group, or a C 3-6 aryl, C 2-6 heterocyclic, or C 6-8 arylalkyl group optionally substituted by a hydroxyl group, a C 1-3 alkyl group, or a C 1-3 alkoxy group.

5. The process according to claim 1 , wherein R a and R b represent, independently from each other, a C 3-6 heterocyclic group comprising from 1 to 3 heteroatoms selected from nitrogen, oxygen, and sulphur.

6. The process according to claim 1 , wherein the catalyst or the pre-catalyst is of formula
[Ru(PP)(NN) n (RCOO) 2 ]  (1)

wherein PP, NN, R, and n have the same meaning as defined in claim 1 .

7. The process according to claim 6 , wherein the RCOO group of (I) is selected from the group consisting of isobutyrate, pivalate, t Bu-acetate, trifluoroacetate, 2-Et-hexanoate, cyclohexanecarboxylate, picolinate, cinnamate, benzoate, 4-Me-benzoate, 4-OMe-benzoate, 3,5-dichloro-benzoate, 2,4-dichloro-benzoate, isovalerate, adamantate, and sec-butyrate.

8. The process according to claim 1 , wherein the bidentate NN ligand is a compound of formula

wherein a and a′, simultaneously or independently, represent 0 or 1, when a′ is 0 then the nitrogen atom is part of an aromatic heterocycle;
the R 1 , taken separately, represent, simultaneously or independently, a hydrogen atom or a C 1-6 linear, branched, or cyclic alkyl group optionally substituted or a phenyl or a benzyl group optionally substituted; two R 1 , taken together, may form a saturated heterocycle containing 3 to 7 atoms and including the atoms to which said le are bonded, said heterocycle being optionally substituted;
R 2 and R 3 , taken separately, represent, simultaneously or independently, a hydrogen atom, a C 1-6 linear, branched alkyl group optionally substituted, or a C 6-10 aromatic group optionally substituted; a R 1 and an adjacent R 2 , taken together, may form a saturated or unsaturated heterocycle containing 5 to 8 atoms and including the atoms to which said R 1 and R 2 are bonded, and optionally containing one additional nitrogen or oxygen atom; two R 2 , taken together, may form a saturated or unsaturated ring having 5 to 8 atoms and including the carbon atoms to which said two R 2 groups are bonded, said ring optionally containing one additional nitrogen and/or oxygen atom; and
Q represents a group of formula

wherein m is 1 or 2, and R 5 and R 6 represent, simultaneously or independently, a hydrogen atom, a C 1-6 linear, branched, or cyclic alkyl group optionally substituted or a C 6-10 aromatic group optionally substituted; two distinct R 6 and/or R 5 groups, taken together, may form a C 3-8 saturated ring optionally substituted, including the atoms to which said R 6 and/or R 5 groups are bonded, and optionally containing one or two additional nitrogen or oxygen atoms.

9. The process according to claim 8 , wherein a is 0.

10. The process according to claim 8 , wherein the bidendate (NN) ligand is selected from the group consisting of ethane-1,2-diamine, N,N-dimethylethane-1,2-diamine, N,N,N′,N′-tetramethylethane-1,2-diamine, 1,2-diphenylethane-1,2-diamine, (1R,2R)-1,2-diphenylethane-1,2-diamine, cyclohexane-1,2-diamine, (1R,2R)-cyclohexane-1,2-diamine, propane-1,3-diamine, and pyridin-2-ylmethanamine.

11. The process according to claim 1 , wherein the bidentate ligand (PP) is a compound of formula

wherein R 11 and R 12 , when taken separately, represent, simultaneously or independently, a C 1-6 linear alkyl group optionally substituted, a C 3-6 branched or cyclic alkyl group optionally substituted, or a C 6-10 aromatic group optionally substituted; and
Q′ represents
a group of formula

wherein m′ is 1, 2, 3 or 4; and
R 5′ and R 6′ represent, simultaneously or independently, a hydrogen atom, a C 1-6 linear or branched alkyl group optionally substituted or a C 6-10 aromatic group optionally substituted; two distinct R 6′ and/or R 5′ groups, taken together, may form a C 3 to C 8 saturated or unsaturated ring optionally substituted, including the atoms to which said R 6′ and/or R 5′ groups are bonded, and optionally containing one or two additional nitrogen or oxygen atoms; or
a C 10 -C 16 metallocenediyl, a 2,2′-diphenyl, a 1,1′-binaphthalene-2,2′-diyl, a benzenediyl, a na

Assignees

• Firmenich & Cie

Inventors

• Saudan Lionel

Classifications

• B01J31/2457

  comprising aliphatic or saturated rings, e.g. Xantphos · CPC title

• B01J31/2409

  with more than one complexing phosphine-P atom · CPC title

• C07C209/52

  by reduction of imines or imino-ethers (C07C209/24 takes precedence) · CPC title

• B01J31/1805

  the ligands containing nitrogen · CPC title

• B01J31/2452

  with more than one complexing phosphine-P atom · CPC title