Recent Patents on Catalysis, 2012, 1, 27-34
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Application of Chirally Modified Nickel Catalysts for Production of Optically Active Compounds Tsutomu Osawaa* and Victor Borovkovb,c* a
Graduate School of Science and Engineering for Research, University of Toyama, Gofuku, Toyama 930-8555, Japan; Metek Kitamura Co., Ltd., 1 Warada-cho, Kamitoba, Minami-ku, Kyoto 601-8133, Japan; cDepartment of Applied Chemistry, Osaka University, 2-1 Yamada-oka, Suita 565-0871, Japan b
Received: November 4, 2011; Accepted: January 20, 2012; Revised: January 17, 2012
Abstract: The major patents concerning chirally modified nickel catalysts by enantiomerically pure tartaric acid are comprehensively surveyed. The methods of catalyst’s preparation for attaining a high enantioselectivity and the synthetic routes for obtaining optically active compounds by using these tartaric acid-modified nickel catalysts are summarized. A recently claimed patent dealing with the robust chiral nickel catalyst, which exhibits an exceptionally high stability after preparation is also introduced.
Keywords: Asymmetric synthesis, chiral catalysts, chiral compounds, enantio-differentiating hydrogenation, methyl acetoacetate, modified nickel catalyst, nickel powder, Raney nickel, tartaric acid. 1. INTRODUCTION The production of chiral substances is a key issue in synthetic organic chemistry, especially in the fields of pharmaceuticals, flavor and aroma-chemicals, as well as agrochemicals [1]. Amongst the various methods for obtaining of optically active compounds, heterogeneous enantio-differentiating catalysis is one of the most suitable approaches for a large scale manufacture in industry because of several environmentally friendly advantages, i.e., i) easy preparation, ii) facile separation, and iii) simple reuse. To this end, chirally modified catalysts on the basis of platinum group metals and metallic nickel have attracted much attention owing to their high enantioselectivity and enhanced catalytic efficiency and hence been intensively studied to date [2, 3]. Each catalytic system has its own substrate specificity, i.e. in general, platinum group metals modified with an optically active dopant (typically, cinchonidine alkaloid) hydrogenate -ketoesters, whilst nickel catalysts modified with a chiral compound (typically, tartaric acid) hydrogenate -ketoesters and 2alkanones in a high enantioselectivity. Chirally modified nickel catalyst was invented by Izumi in 1962 [4]. This catalyst was prepared by adsorption of an optically active modifier (tartaric acid, as a conventional modifier) on its surface to differentiate the re and si faces of prochiral substrate. Tartaric acid is the best modifier amongst over 100 modifiers examined. Tartaric acid modified nickel catalyst attains a high enantioselectivity in the hydrogenation of -ketoesters and 2-alkanones. A number of review articles describing this catalyst have been published so far [5-17] and various *Address correspondence to these authors at the Graduate School of Science and Engineering for Research, University of Toyama, Gofuku, Toyama 9308555, Japan; Tel: 81 76 445 6611; Fax: 81 76 445 6549; E-mail:
[email protected] Metek Kitamura Co., Ltd., 1 Warada-cho, Kamitoba, Minami-ku, Kyoto 601-8133, Japan; cDepartment of Applied Chemistry, Osaka University, 2-1 Yamada-oka, Suita 565-0871, Japan; Tel: 81 6 6879 4128; Fax: 81 6 6879 7923; E-mail:
[email protected]
2211-54 /12 $100.00+.00
factors affecting the enantio-selectivity have been systematically investigated to optimize different parameters for ensuring a high enantio-differentiation and catalytic performance. These factors are listed in Fig. (1) and include the catalyst preparation conditions (type of the Ni catalyst source, crystallite size and structure of Ni, etc.), modification conditions (pH, temperature, type of pH adjusting alkali hydroxide, etc.), and hydrogenation conditions (type of solvent, type and the amount of additives, hydrogenation temperature, etc.). The corresponding mechanisms of these catalytic hydrogenation reactions were also proposed by several research groups [9, 13, 14, 18-25]. Although the major steps of enantiodifferentiation were established, the detailed mechanism is yet to be rationalized. Another important point of this research, such as application of various chiral compounds obtained by tartaric acid modified nickel catalyst has been studied by Tai [15]. The prospective industrial use of the chirally modified nickel catalysts has been also reflected in a number of patents obtained to date. They are summarized in Table 1. In this mini review, the patents published so far are reviewed including a patent recently claimed by our group. 2. PREVIOUS PATENTS ON CHIRALLY MODIFIED NICKEL CATALYST Table 1 shows the patents describing the chirally modified nickel catalysts in the ascending order of the priority date of patent application. The main topics of the patents concerning the chirally modified nickel catalyst are as follows; 1. the preparation method of chirally modified nickel catalyst and 2. the production of optically active compounds using the chirally modified nickel catalysts. In this section, each patent is briefly described and if available, the original paper(s) © 2012 Bentham Science Publishers
28 Recent Patents on Catalysis, 2012, Vol. 1, No. 1
Osawa and Borovkov
Base Ni catalyst Factors affecting enantioselectivity Catalyst preparation process Obtaining hydrogenation activity
Types of base Ni catalyst
Formation of a surface suitable for enantio-differentiating hydrogenation
Catalyst preparation method Conditions of preparation
Nickel catalyst Modification process Types of modification reagent
Formation of a surface suitable for enantio-differentiating hydrogenation
Conditions of modification
Formation of enantio-differentiating site
Modified nickel catalyst
Hydrogenation process
Types of substrate Hydrogenation conditions
Substrate
Optically active product Fig. (1). Factors affecting enantio-selectivity for the enantio-differentiating hydrogenation over modified nickel catalyst. Table 1.
Patents on chirally modified nickel catalyst.
Entry No.
Patent No.
Title
Inventor(s)
Applicant(s)
(Kind)
Priority Date of Patent Application
1
JP 3922943(B)
1962-03-31
Method of preparation of asymmetric reduction catalysts
Akabori S, Izumi Y
Ajinomoto Co., Inc.
2
JP 52005692(A)
1975-07-02
Asymmetric hydrogenation catalyst
Orito Y, Niwa S, Imai S
Agency of Industrial Sciences and Technology, Japan
JP 54036999(B) 3
JP 55124543(A)
1979-03-20
Modified catalyst for stereo-differentiating reduction of carbonyl compounds and process for reduction with same catalyst
Izumi Y, Harada T, Komatsu S
Kawaken Fine Chemicals Co., Ltd., Japan
4
DE 2917752(A1)
1979-05-02
Modified catalyst for stereoselective reduction of carbonyl compounds
Harada T, Izumi Y, Komatsu S
Kawaken Fine Chemicals Co., Ltd., Japan
1981-09-10
Modified nickel catalyst for stereospecific hydrogenation
Izumi Y, Tai A, Harada T, Imachi Y
Kawaken Fine Chemicals Co., Ltd., Japan
DE 2917752(C2) US 4273933(A) 5
JP 58043236(A) JP 63013731(B)
Chirally Modified Nickel Catalyst
Recent Patents on Catalysis, 2012, Vol. 1, No. 1
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(Table 1) Contd…. Entry No.
Patent No.
Title
Inventor(s)
Applicant(s)
(Kind)
Priority Date of Patent Application
6
JP 60036422(A)
1983-08-09
Asymmetric hydrogenation of -ketoesters
Hayashi T
Research Development Corp. of Japan, Japan
JP 04046942(B) 7
JP 61028458(A)
1984-07-20
Modified catalyst for stereospecific reduction of a keto acid ester
Izumi Y, Tai A, Harada T, Tsukioka K, Inoue Y
Kawaken Fine Chemicals Co., Ltd., Japan, Shin-Etsu Chemical Industy Co., Ltd.
8
DD 248579(A1)
1986-04-24
Procedure for the catalytic asymmetric transfer hydrogenation of keto compounds by means of chiral ligand modified group VIIIB transition metals
Boerner A, Krause H
Akademie der Wissenschaften der DDR, Ger. Dem. Rep.
9
JP 02225430(A)
1989-02-27
Preparation of optically active 2,6-dimethyl3,5-heptanediol
Tai A, Sugimura T
Wako Pure Chemical Industries, Ltd., Japan
JP 2838529(B2) EP 385368(A1) EP 385368(B1) US 4990694(A) AT 89541(T) 10
JP 03249946(A)
1990-02-28
Manufacture of highly selective Raney nickel catalyst for reducing carbonyl compounds to optically active material
Kikukawa T, Tai A
Nard Institute Ltd., Japan
11
JP 06025019(A)
1992-07-13
Asymmetric hydrogenation of methyl acetoacetate
Nishijima H, Tanitsu M
Chiyoda Chem. Eng. Construct. Co, Japan
12
JP 09268146(A)
1996-04-01
Process for preparation of optically active fluorine-containing hydroxy compounds by hydrogenation
Fujima T, Asai T, Kumai K
Asahi Glass Co., Ltd., Japan
13
DE 19709069(A1)
1997-03-06
Process for the preparation of enantiomerically pure diesters of 3-hydroxyoctandioic acid by asymmetric catalytic hydrogenation, preparation of (R)-3-hydroxyoctandioc acid ester, (R)-(+)- and (S)-(-)--lipoic acid
Gewald R, Laban G
Asta Medica A.-G., Germany
DE 19709069(C2) EP 863125(A1) EP 863125(B1) AT 209623(T) ES 2167817(T3) PT 863125(E) CA 2231093(A1) CA 2231093(C) JP 10273476(A) US 6013833(A) US 6229042(B1) 14
JP 11035520(A)
1997-05-19
Preparation of optically active 3-cyclopropyl3-hydroxypropionic acids
Tai A, Sugimura T, Nakagawa S
Toyo Kasei Kogyo Co.. Ltd., Japan
15
JP 2001354615(A)
2000-06-16
Preparation of optically active 2,4dihydroxyglutaric acid salts and their intermediates
Sugimura T, Nakagawa S
Toyo Kasei Kogyo Co.. Ltd., Japan
16
not opened yet
2011-06-06
Ikeda S, Borovkov V, Kitamura T, Osawa T, Inoue Y
Metek Kitamura Co., Ltd., Japan
30 Recent Patents on Catalysis, 2012, Vol. 1, No. 1
Osawa and Borovkov
related to the patent are listed according the abovementioned topics. 2.1. Preparation Method of Chirally Modified Nickel Catalysts The first class of reviewed patents describes the preparation methods of corresponding chirally modified nickel catalysts used for the hydrogenation reaction of prochiral substrates (typically, methyl acetoacetate). The Entry 1 patent is the firstly reported invention concerning the chirally modified nickel catalyst dated by 1962. It describes the preparation method as follows. Raney nickel alloy was digested in a 25% NaOH solution at 353 K. The resulting Raney nickel catalyst was soaked in a tartaric acid solution adjusted to pH 3~10 by a NaOH solution at 273~373 K. The obtained tartaric acid-modified Raney nickel was employed for the hydrogenation of methyl acetoacetate. The enantioselectivity of 36% was attained see Fig. (2). O
O
(R,R)-Tartaric acid-modified Ni OCH3
OH
O OCH3
Fig. (2). Hydrogenation of methyl acetoacetate over tartaric acidmodified Ni catalyst.
Subsequently, Izumi et al. published the first original paper in 1963 [26], and then summarized their early work on the chirally modified nickel catalyst in the review [5]. The next patent (Entry 2) describes the Ni-diatomaceous earth catalyst containing a small amount of Pt group metals. The catalyst was prepared by the co-precipitation method. Diatomaceous earth was soaked in an aqueous solution of NiSO4 and H2PtCl6. Then a Na2 CO3 solution was added, filtered, washed, and dried to give a mixture containing Ni, Pt, diatomaceous earth in a 1:0.01:1 ratio. This precursor was subsequently reduced at 573 K by a stream of H2 and soaked in a tartaric acid solution. The hydrogenation of methyl acetoacetate resulted in 58~73% enantioselectivity depending upon the conditions of catalyst preparation. Later Orito et al. reported the effects of addition of Pt group metals in the literatures [27-30]. The patents of Entry 3 and 4 report the effect of addition of alkali halide into the modification solution on enantioselectivity. They claimed that the catalyst modified with the aqueous solution of tartaric acid and alkali halide, such as NaBr, resulted in 83% enantioselectivity for the hydrogenation of methyl acetoacetate. The original papers related to this patent were also published [31, 32]. The Entry 5 patent concerns the modified nickel catalyst embedded in a gas-permeable silicone rubber. Hence, 0.8 g of the chirally modified catalyst prepared by the similar procedure as described in the Entry 3 patent was kneaded with 2.4 g of silicone rubber vulcanized at room temperature and 1 mL of methyl propionate. This mixture was processed to a sheet, and left to stand for 2 weeks. The rolled catalyst can be repeatedly used for more than 40 times without a considerable decrease in the enantioselectivity (50~80%) of hydro-
genation of methyl acetoacetate. The related original papers are available as well [33, 34]. The patent of Entry 6 deals with the chirally modified catalyst prepared from the superfine nickel particles (average diameter
