Method for aerobic oxidative coupling of thiophenes with a ligand-supported palladium catalyst

Patent metadata

Field	Value
Publication number	US-10858334-B2
Application number	US-201916243394-A
Country	US
Kind code	B2
Filing date	Jan 9, 2019
Priority date	Jan 9, 2018
Publication date	Dec 8, 2020
Grant date	Dec 8, 2020

Abstract

An oxidative homocoupling method of synthesizing certain 2,2′-bithiophenes from thiophenes using oxygen as the terminal oxidant is disclosed. In non-limiting examples, the method uses oxygen along with a catalytic system that includes palladium, an assistive ligand, and a non-palladium metal additive to catalyze one of the following reactions:

Associated catalytic systems and compositions are also disclosed.

First claim

We claim:

1. A method for synthesizing a 2,2′-bithiophene from two thiophenes, the method comprising:
contacting the two thiophenes with oxygen gas and a catalyst comprising palladium and a ligand selected from the group consisting of a pyridine; a 1,10-phenanthroline; a 2,2′-bipyridine, a 2,2′-bipyrimidine; a 4,5-diazafluoren-9-one; a quinoline; a 1,10-phenanthroline-5,6-dione; a bis(arylimino)acenaphthene; and a 2,2′-biquinoline;
whereby the two thiophenes are covalently coupled by aerobic oxidation to form the 2,2′-bithiophene;
wherein the two thiophenes are not substituted exclusively with alkyl groups, alkoxy groups, alkanoate groups, alkanamide groups, alkoxyalkyl groups, and benzoalkyl groups.

2. The method of claim 1 , wherein the 2,2′-bithiophene that is synthesized has the chemical structure:

and
the two thiophenes have the chemical structure:

wherein X is a halogen, an alkyl, a trimethylsilyl (TMS), a thiophenyl, or a dioxolanyl:
and wherein R 1 and R 2 are each independently selected from the group consisting of hydrogen, bromine, chlorine, fluorine, an alkoxycarbonyl group, an oxoalkyl group, and an alkyl group.

3. The method of claim 2 , wherein the two thiophenes are 2,3-dibromothiophene, 2,4-dibromothiophene, 2-bromo-4-fluorothiophene 2-bromo-3-dodecylthiophene, 2-bromothiophene, 2-chlorothiophene, 2-bromo-3-methylthiophene, 2-bromo-3-hexylthiophene, 2-chloro-3-hexylthiophene,

and wherein the corresponding 2,2′-bithiophene is 4,4′,5,5′-tetrabromo-2,2′-bithiophene (X is bromine, R 1 is bromine, and R 2 is hydrogen), 3,3′,5,5′-tetrabromo-2,2′-bithiophene (X is bromine, R 1 is hydrogen, and R 2 is bromine), 5,5′-dibromo-3,3′-difluoro-2,2′-bithiophene (X is bromine, R 1 is hydrogen, and R 2 is fluorine), 5,5′-dibromo-4,4′-didocecyl-2,2′-bithiophene (X is bromine, R 1 is n-dodecyl, and R 2 is hydrogen), 5,5′-dibromo-2,2′-bithiophene (X is bromine, R 1 is hydrogen, and R 2 is hydrogen), 5,5′-dichloro-2,2′-bithiophene (X is chlorine, R 1 is hydrogen, and R 2 is hydrogen), 5,5′-dibromo-4,4′-dimethyl-2,2′-bithiophene (X is bromine, R 1 is methyl, and R 2 is hydrogen), 5,5′-dibromo-4,4′-dihexyl-2,2′-bithiophene (X is bromine, R 1 is n-hexyl, and R 2 is hydrogen) 5,5′-dichloro-4,4′-dihexyl-2,2′-bithiophene (X is chlorine, R 1 is n-hexyl, and R 2 is hydrogen),

4. The method of claim 1 , wherein the 2,2′-bithiophene that is synthesized is a 2,2′-bibenzo[b]thiophene, and wherein the two thiophenes are benzo[b]thiophenes.

5. The method of claim 4 , wherein the 2,2′-bibenzo[b]thiophene has the chemical structure:

and
the two benzo[b]thiophenes have the chemical structure:

wherein R 1 , R 2 , R 3 , R 4 and R 5 are independently selected from the group consisting of hydrogen and bromine.

6. The method of claim 5 , wherein the 2,2′-bibenzo[b]thiophene that is synthesized is 3,3′-dibromo-2,2′-bibenzo[b]thiphene or 2,2′-bibenzo[b]thiophene, and wherein the two benzo[b]thiophenes are 3-bromobenzo[b]thiophene (R 1 is bromine; R 2 , R 3 , R 4 and R 5 are all hydrogen) or unsubstituted benzo[b]thiophene R 2 , R 3 , R 4 and R 5 are all hydrogen).

7. The method of claim 1 , wherein the 2,2′-bithiophene that is synthesized is a 5,5′-bis-(1-oxoalkyl)-2,2′-bithiophene, and wherein the two thiophenes are 2-(1-oxoalkyl)thiophenes.

8. The method of claim 7 , wherein the 5,5′-bis-(1-oxoalkyl)-2,2′-bithiophene has the chemical structure:

and
the two 2-(1-oxoalkyl)thiophenes have the chemical structure:

wherein R 1 is selected from the group consisting of an alkyl group and hydrogen.

9. The method of claim 8 , wherein the 5,5′-bis-(1-oxoalkyl)-2,2′-bithiophene that is synthesized is 5,5′-bis(trimethylacetyl)-2,2′-bithiophene or 5,5′-bis(carbaldehyde)-2,2′-bithiophene, and wherein the two 2-(1-oxoalkyl)thiophenes are 2-trimethylacetylthiophene (R 1 is tert-butyl; R 2 and R 3 are hydrogen) or thiophene-2-carbaldehyde (R 1 , R 2 , and R 3 are all hydrogen).

10. The method of claim 1 , wherein the 2,2′-bithiophene analog that is synthesized is a 5,5′-bithiazole, and wherein the two thiophene analogs are thiazoles.

11. The method of claim 10 , wherein the 5,5′-bithiazole has the chemical structure:

and
the two thiazoles have the chemical structure:

wherein R 1 is hydrogen and R 2 is bromine.

12. The method of claim 1 , wherein the ligand is selected from the group consisting of a 1,10-phenanthroline-5,6-dione; a 2,2′-bipyridine, a 2,2′-bipyrimidine; a 4,5-diazafluoren-9-one; a quinoline; a 1,10-phenanthroline; a bis(arylimino)acenaphthene; and a 2,2′-biquinoline.

13. The method of claim 12 , wherein the ligand is selected from the group consisting of:
(a) a 1,10-phenanthroline-5,6-dione having the chemical formula:

wherein
(i) 1, 2, 3, 4, or 5 of R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are hydrogen, or
(ii) all six of R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are hydrogen (the ligand is 1,10-phenanthroline-5,6-dione (phd));
(b) a 2,2′-bipyridine having the chemical formula:

wherein one or more of R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 and R 5 are independently selected from the group consisting of hydrogen, tert-butyl, methoxy, methyl, phenyl, and trifluoromethyl;
(c) a 2,2′-bipyrimidine having the chemical formula:

wherein one or more of R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 is hydrogen;
(d) a 4,5-diazafluoren-9-one having the chemical formula:

wherein one or more of R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 is hydrogen;
(e) a quinoline having the chemical formula:

wherein one or more of R 1 , R 2 , R 3 , R 4 , R 5 , R 6 and R 7 is hydrogen;
f) a 1,10-phenanthroline having the chemical formula:

wherein one or more of R 1 , R 2 , R 3 , R 4 , R 5 , R 6 R 7 , and R 8 is independently selected form the group consisting of hydrogen, methyl, and phenyl;
(g) a bis(arylimino)acenaphthene having the chemical formula:

Assignees

• Wisconsin Alumni Res Found

Inventors

• Stahl Shannon
• Tereniak Stephen

Classifications

• B01J2540/225

  comprising perfluoroalkyl groups or moieties · CPC title

• B01J2540/22

  comprising fluorine, e.g. trifluoroacetate · CPC title

• B01J2540/10

  Non-coordinating groups comprising only oxygen beside carbon or hydrogen · CPC title

• B01J2231/46

  C-H or C-C activation · CPC title

• B01J2540/40

  Non-coordinating groups comprising nitrogen · CPC title