Methods for making immobilized aryl-containing ligands
View Patent ↗Organic ligands that contain at least one aryl group are immobilized on a solid support. The organic ligands are of the type used to form a catalyst complex suitable for carrying out a catalytic reaction, preferably an asymmetric reaction. To immobilize the organic ligands, a tethering group is bonded to the ligand using, for example, a Friedel-Crafts acylation or alkylation reaction. The immobilization of the organic ligand can be carried out using a single reaction with the organic ligand.
1. A method for immobilizing an aryl-containing organic ligand, comprising:
combining together the following in a single reaction medium:
an organic ligand comprising at least one aryl group or functionalized aryl group;
a functionalized support material having a plurality of available functional groups; and
a tethering agent having an anchoring functional group selected so as to bond with the functionalized support material and a bonding functional group that is selected so as to bond with the aryl group or functionalized aryl group,
wherein the anchoring functional group is selected so as to react with the functionalized support material in the same reaction medium as a reaction medium used to react the bonding functional group with the aryl group or functionalized aryl group of the organic ligand; and
in the single reaction medium, (i) reacting the bonding functional group of the tethering agent with the aryl group or functionalized aryl group of the organic ligand and (ii) reacting the anchoring functional group of the tethering agent with an available functional group of the support material, so as to yield an aryl-containing organic ligand immobilized on the support material wherein the bonding functional group of the tethering agent is an alkyl halide or an acyl halide and the reaction of the bonding functional group is a Freidel-Crafts alkylation reaction or a Freidel-crafts acylation reaction.
2. A method as in claim 1 , wherein the bonding functional group and the anchoring functional group are a dialkyl halide or a diacyl halide.
3. A method as in claim 1 , where the bonding functional group of the tethering agent reacts with the aromatic ring of the aryl group.
4. A method as in claim 1 , wherein the reaction of the bonding functional group and the reaction of the anchoring functional group occur simultaneously.
5. A method as in claim 1 , wherein the organic ligand is a ligand that can be used to manufacture a chiral catalyst.
6. A method as in claim 1 , wherein the tethering agent is selected from the group consisting of polyfunctional carboxylic acids, polyacids with functionality of three or greater, polymeric acids, hydroxy acids, alkyl halides, acyl halides, nitriles, pyridines and derivatives thereof.
7. A method as in claim 1 , wherein the tethering agent is selected from the group consisting of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, citric acid polyacrylic acid, glycolic acid, salicylic acid, hydroxy propanoic acid, compounds of the general formula HO(CH x ) n COCl, compounds of the general formula HOOC(CH x ) n COCl, compounds of the general formula ClOC(CH x ) n COCl, hydroxyacetonitrile, 3-hydroxyproprionitrile, 2-hydroxyisobutyronitrile, carboxyacetonitrile, 2-hydroxymethylpyridine, picolinic acid (2-pyridine carboxylic acid), nicotinic acid (3-pyridine carboxylic acid), quinolinic acid (2,3-pyridine dicarboxylic acid), and combinations thereof.
8. A method as in claim 1 , wherein the aryl group is selected from the group consisting of benzene, indene, naphthalene, fluorine, chrysene, phenanthrene, anthracene, triphenylene, and aryl-O and aryl-N derivatives thereof, with the proviso that the groups do not include electron withdrawing substituents.
9. A method as in claim 1 , wherein the organic ligand is selected from the group consisting of BINAP, BICHEP, DIPAMP, BINAPHANE, BINAPO, BDPAB, and alkyl, alkyl-O, or alkyl-N derivatives thereof, with the proviso that the derivatives do not have electron withdrawing group substituents.
10. A method as in claim 1 , wherein the support material further comprises extender groups and the available functional groups of the support material are provided by the extender groups.
11. A method as in claim 1 , after the tethering agent is bonded to the organic ligand the method further comprising complexing the organic ligand with a metal atom.
12. A method as in claim 1 , further comprising complexing the organic ligand with a metal atom prior to bonding the organic ligand to the tethering agent.
13. A method as in claim 1 , wherein the tethering agent provides a separation of at least 3 atoms between the support material and the organic ligand.
14. A method as in claim 1 , wherein the tethering agent provides a separation of at least 8 atoms between the support material and the organic ligand.
15. A method as in claim 1 , wherein the support material is selected from the group consisting of alumina, silica, zirconia, titania, ceria, natural and synthetic zeolites, clay, reverse phase silica, and combinations thereof.
16. A method as in claim 1 , wherein the support material is selected from the group consisting carbon black, activated carbon, graphite, polymers, resins.
17. A method for immobilizing an aryl-containing organic ligand, comprising:
providing an organic ligand comprising at least one aryl group;
providing a functionalized support material having a plurality of available functional groups;
providing a tethering agent comprising a plurality of molecules, each having (i) a bonding functional group comprising a leaving group, and (ii) an anchoring functional group selected so as to bond with the functionalized support material wherein the bonding functional group of the tethering agent is alkyl halide or an alkyl halide;
reacting the tethering agent with the organic ligand in a Freidel-Crafts alkylation reaction or a Freidel-Crafts-acylation reaction so as to form a carbon-carbon bond between the tethering agent and the aryl group of the organic ligand; and
reacting the anchoring functional group of the tethering agent with an available functional groups of the functionalized support material.
18. A method as in claim 17 , wherein the anchoring functional group is an acyl halide or an alkyl halide.
19. A method as in claim 17 , wherein the support material further comprises extender groups and the extender groups provide the available functional groups.
20. A method as in claim 17 , wherein the available functional groups of the support material comprise an amine or an aromatic group.
21. A method as in claim 17 , wherein the reactions of the tethering agent with the support material and the tethering agent with the organic ligand are carried out in a single reaction step.
22. A method as in claim 17 , wherein the reaction of the tethering group to the support material occurs in a subsequent reaction to the reaction of the bonding group to the aryl group.