Bisphosphine ligand
A compound represented by the following general formula (I): [wherein R 1 represents hydrogen atom, or an alkyl group, R 2 represents a hydroxyalkyl group, or a triarylmethyloxyalkyl group, or R 1 and R 2 combine together to represent —C(R 3 )(R 4 )— (R 3 and R 4 represent hydrogen atom, an alkyl group, or hydroxyl group, or R 3 and R 4 may combine together to represent oxo group), or —C(R 5 )(R 6 )—O—C(R 7 )(R 8 )— (R 5 to R 8 represent hydrogen atom, an alkyl group, or hydroxyl group, or R 5 and R 6 may combine together to represent oxo group, and R 7 and R 8 may combine together to represent oxo group); Ar 1 to Ar 4 independently represent an aryl group (the aryl group may have 1 to 5 of the same or different substituents), *1 to *4 indicate asymmetric carbons, and configurations are cis between *1 and *2, cis between *3 and *4, and trans between *2 and *3]. An optically active phosphine ligand which can be easily synthesized and gives a transition metal complex showing superior asymmetric catalyst activity is provided.
1. A compound represented by the following general formula (I):
wherein
R 1 represents a hydrogen atom or an alkyl group,
R 2 represents a hydroxyalkyl group or a triarylmethyloxyalkyl group, or
R 1 and R 2 combine together to represent —C(R 3 )(R 4 )—, wherein
R 3 and R 4 independently represent a hydrogen atom, an alkyl group, or a hydroxyl group, or
R 3 and R 4 may combine together to represent an oxo group, or R 1 and R 2 combine together to represent —C(R 5 )(R 6 )—O—C(R 7 )(R 8 )—, wherein
R 5 , R 6 , R 7 and R 8 independently represent a hydrogen atom, an alkyl group, or a hydroxyl group, or
R 5 and R 6 may combine together to represent an oxo group, and/or
R 7 and R 8 may combine together to represent an oxo group; and
wherein
Ar 1 , Ar 2 , Ar 3 Ar 4 independently represent aryl group, which may have 1 to 5 of the same or different substituents, and wherein
*1, *2, *3 and *4 indicate asymmetric carbons, and relative steric configurations thereof are in cis-configuration between *1 and *2, cis-configuration between *3 and *4, and trans-configuration between *2 and *3.
2. The compound according to claim 1 , wherein Ar 1 , Ar 2 , Ar 3 and Ar 4 independently represent a phenyl group, which may have 1 to 5 of the same or different substituents.
3. The compound according to claim 1 , wherein Ar 1 , Ar 2 , Ar 3 and Ar 4 independently represent a phenyl group, or a 3,5-dialkyl-4-alkoxyphenyl group.
4. The compound according to claim 1 , wherein R 1 is a hydrogen atom, and R 2 is a hydroxyalkyl group.
5. The compound according to claim 1 , wherein R 1 is a hydrogen atom; or an alkyl group, and R 2 is a triphenylmethyloxyalkyl group.
6. The compound according to claim 1 , wherein R 1 and R 2 combine together to represent —C(R 3 )(R 4 )—, wherein R 3 and R 4 both represent a hydrogen atom, or R 3 and R 4 combine together to represent an oxo group.
7. The compound according to claim 1 , wherein R 1 and R 2 combine together to represent —C(R 5 )(R 6 )—O—C(R 7 )(R 8 )—, wherein R 5 and R 6 independently represent an alkyl group, and both R 7 and R 8 are hydrogen atoms.
8. The compound according to claim 1 and a transition metal, which together form a transition metal complex.
9. The transition metal complex according to claim 8 , wherein the transition metal is selected from rhodium, ruthenium, iridium, and palladium.
10. A catalyst for an asymmetric reaction, which comprises the transition metal complex according to claim 9 .
11. The catalyst according to claim 10 , which is used for an asymmetric hydrogenation reaction of an olefin, an imine, or a ketone, or an asymmetric 1,4-addition reaction of an enone.
12. A phosphine borane compound consisting of the compound according to claim 1 having boranes added on each of the two phosphorus atoms of the compound.
13. A method for preparing the compound according to claim 1 comprising:
having boranes added on each of the two phosphorus atoms of the compound and
treating a phosphine borane compound, consisting of the compound according to claim 1 having boranes added on each of the two phosphorus atoms of the compound, with a base.