Catalysts

Abstract

Catalysts suitable for asymmetric hydrogenation reactions is described comprising the reaction product of a group (8) transition metal compound a chiral phosphine and a chiral diamine of formula (1) in which R 1 , R 2 R 3 or R 4 are independently hydrogen, a saturated or unsaturated alkyl, or cycloalkyl group, an aryl group, a urethane or sulphonyl group and R 5 , R 6 , R 7 or R 8 are independently hydrogen, a saturated or unsaturated alkyl or cycloalkyl group, or an aryl group, at least one of R 1 , R 2 , R 3 or R 4 is hydrogen and A is a linking group comprising one or two substituted or unsubstituted carbon atoms.

1 . A chiral catalyst comprising the reaction product of a ruthenium compound, a chiral bis(phosphine) selected from P-Phos, tol-P-Phos or xyl-P-Phos and a chiral diamine of formula (I)  
     
       
         
         
             
             
         
       
     
     in which R 1 , R 2 , R 3  or R 4  are independently hydrogen, a saturated or unsaturated alkyl, or cycloalkyl group, an aryl group, a urethane or sulphonyl group and R 5 , R 6 , R 7  or R e  are independently hydrogen, a saturated or unsaturated alkyl or cycloalkyl group, or an aryl group, at least one of R 1 , R 2 , R 3  or R 4  is hydrogen and A is a linking group comprising one or two substituted or unsubstituted carbon atoms.  
   
   
       2 . (canceled)  
   
   
       3 . A catalyst according to  claim 1  wherein R 1 , R 2 , R 3  and R 4  are the same or different and are selected from hydrogen, methyl, ethyl, isopropyl, cyclohexyl, phenyl or 4-methylphenyl groups.  
   
   
       4 . A catalyst according to  claim 1  wherein R 1  and R 2  are linked or R 3  and R 4  are linked so as to form a 4 to 7-membered ring structure incorporating the nitrogen atom.  
   
   
       5 . A catalyst according to  claim 1  wherein R 5 , R 6 , R 7  and R 8  are the same or different and are selected from hydrogen, methyl, ethyl, propyl, iso-propyl, butyl, iso-butyl, sec-butyl, tert-butyl, cyclohexyl or substituted or unsubstituted phenyl or naphthyl groups.  
   
   
       6 . A catalyst according to  claim 1  wherein one or more of R 5 , R 6  R 7  or R e  form one or more ring structures with the linking group A.  
   
   
       7 . A catalyst according to  claim 1  wherein a substituting group on the carbon atom of linking group A is alkyl (C1-C20), alkoxy (C1-C20) or amino or forms one or more ring structures incorporating one or more carbon atoms making up the linking group.  
   
   
       8 . A catalyst according to  claim 1  wherein the chiral diamine is of formula (II)  
     
       
         
         
             
             
         
       
     
     wherein B is a linking group comprising one or two substituted or unsubstituted carbon atoms.  
   
   
       9 . A catalyst according to  claim 8  wherein R 1 , R 2 , R 3 , R 4  are hydrogen, R 5 , R 6 , R 7  and R 8  are hydrogen or alkyl groups and B comprises C(CH 3 ) 2  or (CH 3 )(OCH 3 )C—C(CH 3 (OCH 3 ).  
   
   
       10 . A catalyst according to  claim 8  wherein the chiral diamine is selected from 3-Aminomethyl-5-6-dimethoxy-5-6-Dimethyl[1,4]-dioxan-2-yi]-methylamine (DioBD) or 2,3-O-isopropylidenebutane 1,4 diamine (DAMTAR).  
   
   
       11 . A catalyst according to  claim 1  wherein the chiral diamine is of formula (III)  
     
       
         
         
             
             
         
       
     
     wherein R′ is a protecting group.  
   
   
       12 . A catalyst according to  claim 11  wherein R 1 , R 2  and R 5  are hydrogen, R 3  and R 4  are hydrogen or alkyl, R 7  and R 8  are hydrogen, alkyl or aryl and R′ is selected from an alkyl, aryl, carboxylate, amido or sulphonate protecting group.  
   
   
       13 . A catalyst according to  claim 11  wherein the chiral diamine is 4-Amino-2-aminomethylpyrrolidine-1-carboxylic acid tent-butyl ester (PyrBD).  
   
   
       14 . A catalyst according to  claim 1  wherein the chiral diamine is of formula (IV)  
     
       
         
         
             
             
         
       
     
   
   
       15 . A catalyst according to  claim 14  wherein R 1 , R 2 , R 3 , R 4 , R 6 , R 7  are hydrogen and R 5  and R 8  are aryl or substituted aryl groups.  
   
   
       16 . A catalyst according to  claim 14  wherein the chiral diamine is Diphenyl-1,3-propanediamine (Dppn).  
   
   
       17 . A catalyst according to  claim 1  wherein the chiral diamine is of formula (V).  
     
       
         
         
             
             
         
       
     
     wherein n=1 or 2.  
   
   
       18 . A catalyst according to  claim 17  wherein R 5  and R 8  are hydrogen.  
   
   
       19 . A method for the asymmetric hydrogenation of ketones and imines comprising contacting a ketone or imine with a strong base and a chiral catalyst comprising the reaction product of a ruthenium compound, a chiral bis(phosphine) selected from P-Phos, tol-P-Phos or xyl-P-Phos and a chiral diamine of formula (I)  
     
       
         
         
             
             
         
       
     
     in which R 1 , R 2 , R 3  or R 4  are independently hydrogen, a saturated or unsaturated alkyl, or cycloalkyl group, an aryl group, a urethane or sulphonyl group and R 5 , R 6 , R 7  or R e  are independently hydrogen, a saturated or unsaturated alkyl or cycloalkyl group, or an aryl group, at least one of R 1 , R 2 , R 3  or R 4  is hydrogen and A is a linking group comprising one or two substituted or unsubstituted carbon atoms.  
   
   
       20 . The method according to  claim 19 , wherein the ketone is an alkyl ketone of formula RCOR′ in which R and R′ are substituted or unsubstituted, saturated or unsaturated C1-C20 alkyl or cycloalkyl which may be linked and form part of a ring structure.