Process for hydrogenating ketones in the presence of Ru(II) catalysts
The present invention relates to a process for hydrogenating a substrate including a carbon-heteroatom double bond, the process including the step of reacting the substrate with hydrogen gas in the presence of a hydrogenation catalyst, wherein the hydrogenation catalyst is a complex of formula (I): R 1-10 , A and Hal are as defined in the specification. The present invention also provides processes for the preparation of the complex of formula (I) and intermediates thereof.
1. A complex of formula (I):
wherein,
R 1 , R 2 , R 3 , R 4 and R 5 are each independently hydrogen, straight-chained or branched C 1-10 alkyl;
R 6 , R 7 , R 8 and R 9 are each independently hydrogen or phenyl; or
one of R 6 or R 7 and one of R 8 and R 9 together form a C 5-20 cycloalkyl or a C 5-20 cycloalkoxy;
R 10 is 2,4,6-trimethylphenyl, 2,4,6-triisopropylphenyl, or pentamethylphenyl;
A is a straight chain C 2-5 alkylene; and
Hal is a halogen.
2. The complex of claim 1 , wherein R 1 , R 2 , R 3 , R 4 and R 5 are each independently hydrogen, methyl, ethyl, n-propyl, propyl, n-butyl, i-butyl, s-butyl or t-butyl.
3. The complex of claim 2 , wherein R 1 , R 2 , R 3 , R 4 and R 5 are each hydrogen.
4. The complex of claim 1 , wherein one of R 6 and R 7 is phenyl and the other of R 6 and R 7 is hydrogen.
5. The complex of claim 1 , wherein one of R 8 and R 9 is phenyl and the other of R 8 and R 9 is hydrogen.
6. The complex of claim 1 , wherein R 6 , R 7 , R 8 and R 9 are hydrogen.
7. The complex of claim 1 , where R 10 is a 2,4,6-triisopropylphenyl.
8. The complex of claim 1 , where A is butylene.
9. The complex of claim 7 that is:
10. The complex of claim 9 , that is an R,R or S,S stereoisomer thereof.
11. The complex of claim 1 , where R 10 is a 2,4,6-trimethylphenyl.
12. The complex of claim 11 that is:
13. The complex of claim 12 , that is an R,R or S,S stereoisomer thereof.
14. The complex of claim 1 , where R 10 is a pentamethylphenyl.