Oxotitanium complex, asymmetric hydrogenation catalyst comprising the complex, and process for producing .beta.-hydroxy ketone or .alpha.-hydroxy carboxylic acid ester using the complex

• US 5,616,751 A
• Filed: 03/10/1995
• Issued: 04/01/1997
• Est. Priority Date: 03/11/1994
• Status: Expired due to Term

• Current Assignee: Takasago International Corporation
• Original Assignee: Takasago International Corporation
• Inventors: Kitamoto, Dai, Nakai, Takeshi, Sayo, Noboru
• Primary Examiner(s): Killos, Paul J.
• Application Number:
  US08/401,800
• Time in Patent Office: 753 Days
• Field of Search: 556/54
• US Class Current: 556/54
• CPC Class Codes: B01J 2231/341 1,2-additions, e.g. aldol or Knoevenagel condensations
• CPC Class Codes: B01J 2531/0266 Axially chiral or atropisomeric ligands, e.g. bulky biaryls such as donor-substituted binaphthalenes, e.g. "BINAP" or "BINOL"
• CPC Class Codes: B01J 2531/46 Titanium
• CPC Class Codes: B01J 2540/34 Sulfonyl groups
• CPC Class Codes: B01J 31/2226 Anionic ligands, i.e. the overall ligand carries at least one formal negative charge
• CPC Class Codes: B01J 31/223 At least two oxygen atoms present in one at least bidentate or bridging ligand
• CPC Class Codes: C07C 45/511 involving transformation of singly bound oxygen functional groups to >C = O groups involving two hydroxy groups C07C45/52; hydroperoxides C07C45/53
• CPC Class Codes: C07C 45/72 by reaction of compounds containing >C = O groups with the same or other compounds containing >C = O groups
• CPC Class Codes: C07C 67/343 by increase in the number of carbon atoms
• CPC Class Codes: C07C 67/347 by addition to unsaturated carbon-to-carbon bonds
• CPC Class Codes: C07C 69/732 of unsaturated hydroxy carboxylic acids
• CPC Class Codes: C07F 7/003 without C-Metal linkages

Abstract

A novel oxotitanium complex represented by general formula (I) is disclosed: ##STR1## wherein R¹ and R² may be the same or different and each represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a halogen atom, a phenyl group, a substituted phenyl group, a trialkylsilyl group, a monoalkyldiphenylsilyl group, a dialkylmonophenylsilyl group, a triphenylsilyl group, a substituted triphenylsilyl group, or a lower alkoxycarbonyl group, provided that R¹ and R² may be bonded to each other to form a hydrocarbon ring or a substituted hydrocarbon ring in cooperation with the carbon atoms to which R¹ and R² are bonded; R³ and R⁴ may be the same or different and each represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a benzoyl group, a benzenesulfonyl group, or a halogen atom, provided that R³ and R⁴ may be bonded to each other to form a hydrocarbon ring or a substituted hydrocarbon ring in cooperation with the carbon atoms to which R³ and R⁴ are bonded; and n is 1 or 2. The novel oxotitanium complex is useful as an asymmetric reaction catalyst. A process for producing a β-hydroxy ketone or an α-hydroxy carboxylic acid ester in the presence of the novel oxotitanium complex is also disclosed.

Claims

1. An oxotitanium complex represented by general formula (I):

##STR16## wherein R¹ and R² may be the same or different and each represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a halogen atom, a phenyl group, a substituted phenyl group, a trialkylsilyl group, a monoalkyldiphenylsilyl group, a dialkylmonophenylsilyl group, a triphenylsilyl group, a substituted triphenylsilyl group, or a lower alkoxycarbonyl group, provided that R¹ and R² may be bonded to each other to form a hydrocarbon ring or a substituted hydrocarbon ring in cooperation with the carbon atoms to which R¹ and R² are bonded;

R³ and R⁴ may be the same or different and each represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a benzoyl group, a benzenesulfonyl group, or a halogen atom, provided that R³ and R⁴ may be bonded to each other to form a hydrocarbon ring or a substituted hydrocarbon ring in cooperation with the carbon atoms to which R³ and R⁴ are bonded; and

n is 1 or 2.

2. The oxotitanium complex as claimed in claim 1, wherein R¹ is a group selected from a methyl group, a phenyl group, a substituted phenyl group, a triphenylsilyl group, a substituted triphenylsilyl group, and a lower alkoxycarbonyl group, R² is a hydrogen atom, and R³ and R⁴ are bonded to each other to form, in cooperation with the carbon atoms to which R³ and R⁴ are bonded, either a hydrocarbon ring or a hydrocarbon ring having a substituent selected from a halogen atom, a benzoyl group, and a benzenesulfonyl group.

3. The oxotitanium complex as claimed in claim 1, wherein R¹ is a hydrogen atom, R² is a hydrogen atom, and R³ and R⁴ are bonded to each other to form, in cooperation with the carbon atoms to which R³ and R⁴ are bonded, either a hydrocarbon ring or a hydrocarbon ring having a substituent selected from a halogen atom, a benzoyl group, and a benzenesulfonyl group.

4. The oxotitanium complex as claimed in claim 1, wherein R¹ and R² are bonded to each other to form, in cooperation with the carbon atoms to which R¹ and R² are bonded, either a hydrocarbon ring or a hydrocarbon ring having a substituent selected from a halogen atom, a benzoyl group, and a benzenesulfonyl group, and R³ and R⁴ are bonded to each other to form, in cooperation with the carbon atoms to which R³ and R⁴ are bonded, either a hydrocarbon ring or a hydrocarbon ring having a substituent selected from a halogen atom, a benzoyl group, and a benzenesulfonyl group.

5. The oxotitanium complex as claimed in claim 1, wherein R¹ is a hydrogen atom, R² and R³ each is a hydrogen atom, a halogen atom, or a group selected from a lower alkyl group and a lower alkoxy group, and R⁴ is a methyl group.