Aldehyde-selective wacker-type oxidation of unbiased alkenes
This disclosure is directed to methods of preparing organic aldehydes, each method comprising contacting a terminal olefin with an oxidizing mixture comprising: (a) a dichloro-palladium complex; (b) a copper complex; (c) a source of nitrite; under aerobic reaction conditions sufficient to convert at least a portion of the terminal olefin to an aldehyde.
1. A method comprising contacting a terminal olefin with a Wacker-type oxidation catalyst system mixture comprising:
(a) a dichloro-bis(nitrile) palladium (II) complex; and
(b) copper chloride, either as CuCl or CuCl 2 ;
said Wacker-type oxidation catalyst system mixture further comprising
(c) an inorganic nitrite salt;
said contacting done in the presence of a tertiary alcohol under aerobic reaction conditions sufficient to convert at least a portion of the terminal olefin to an aldehyde, such that the selectivity for aldehyde is at least 50%.
2. The method of claim 1 , wherein the inorganic nitrite salt comprises silver nitrite.
3. The method of claim 1 , wherein the inorganic nitrite salt comprises NaNO 2 or AgNO 2 .
4. The method of claim 1 , wherein the dichloro-bis(nitrile) palladium (II) complex comprises bis(benzonitrile)dichloro-palladium(II).
5. The method of claim 1 , wherein the tertiary alcohol comprises tert-butanol.
6. The method of claim 5 , wherein the the Wacker-type oxidation catalyst system mixture further comprises nitromethane.
7. The method of claim 1 , wherein the terminal olefin has a structure of Formula (1):
wherein:
n=2 to 9; and
R is optionally halogenated benzyl, optionally halogenated phenyl, carboxy acid, carboxy acid ester, cyclohexyl, halogen, —O—C 1-12 -alkyl, hydroxyl, or nitro.
8. A method of converting a terminal olefin to an acetal, acylal, terminal alcohol, α, β-unsaturated aldehyde, aldoxime, anhydride, amide, amine, α-amino nitrile, carboxylic acid, carboxylate ester, α, β-unsaturated carboxylic acid, 1, 3 diol, epoxide, α, β-unsaturated epoxy ester, β-hydroxyester, α-hydroxy nitrile, hydrazone, nitrile, β-nitro alcohol, semicarbazone, halide, gem-dihalide, or α-halo ether, said method comprising:
(a) converting the terminal olefin to a aldehyde according to the method of claim 1 ; and
(b) converting the aldehyde to the acetal, acylal, terminal alcohol, α, β-unsaturated aldehyde, aldoxime, anhydride, amide, amine, α-amino nitrile, carboxylic acid, carboxylate ester, α, β-unsaturated carboxylic acid, 1, 3 diol, epoxide, α, β-unsaturated epoxy ester, β-hydroxyester, α-hydroxy nitrile, hydrazone, nitrile, β-nitro alcohol, semicarbazone, halide, gem-dihalide, or α-halo ether.
9. The method of claim 1 , wherein the molar ratio of the dichloro-bis(nitrile) palladium(II) complex to the copper chloride is about 1:1.
10. The method of claim 1 , wherein the molar ratio of the dichloro-bis(nitrile) palladium(II) complex to the inorganic nitrite salt is about 2:1.
11. The method of claim 1 , wherein the Wacker-type oxidation catalyst system mixture comprises:
(a) bis(benzonitrile)dichloro-palladium(II); and
(b) copper chloride; and wherein
the Wacker-type oxidation catalyst system mixture further comprises
(c) sodium nitrite or silver nitrite.
12. The method of claim 11 , wherein the Wacker-type oxidation catalyst system mixture further comprises tert-butanol.
13. The method of claim 12 , wherein the Wacker-type oxidation catalyst system mixture further comprises nitromethane.
14. The method of claim 11 , wherein the molar ratio of the bis(benzonitrile)dichloro-palladium(II) to the copper chloride complex is about 1:1.
15. The method of claim 11 , wherein the molar ratio of the bis(benzonitrile)dichloro-palladium(II) to the inorganic nitrite salt is about 2:1.