Wacker cyclodextrin

Cyclodextrin transferase Total, approx. /5-Cyclodextrin and other cyclodextrins 3000-4000 180,000 Wacker-Chemie (Germany)... 

One of the earliest use of cyclodextrins as inverse phase transfer agents was in the Wacker oxidation of higher olefins to methyl ketones [22] with [PdCU] + [CuCU] catalyst (Scheme 10.12). Already at that time it was discovered, that cyclodextrins not only transported the olefins into the aqueous phase but imposed a substrate-selectivity, too with Ckh olefins the yields decreased dramatically and 1-tetradecene was only slightly oxidized. 

Similar results were obtained in the biphasic Wacker oxidation of 1-decene, catalyzed by PdS04, CUSO4 and a heteropolyacid H9PV6M06O40 in the presence of chemically modified p-cyclodextrins (methyl, methoxy, hydroxypropyl derivatives). The reactions yielded 2-decanone in rather high yield (up to 58 %) accompanied by extensive isomerization of 1-decene to internal decenes. Nevertheless, these latter apparently did not react, since the ratio of 2-decanone among the oxodecenes exceeded 99 % (Scheme 10.12). 

Cyclodextrines, modified with 2-cyanoethyl and with bis(2-cyanoethyl)amino groups were used as ligands in the [PdCy + [CuCU]-catalyzed Wacker-oxidation of 1-octene. Without the modified cyclodextrins the yield of 2-octanone was less than 1 %, which could be raised to 73 % by the addition of nitrile-modified P-cyclodextrin ligands (60 °C, 2 h). 

PdS04/H9PV6Mo604o/CuS04 in the presence of chemically modified P-cyclodextrins were also used as CPTC systems in the Wacker-type oxidation of higher a-olefins (Cg-Cje) to the corresponding 2-ketones (Equation 18) with high yields (90-98%) in an aqueous/organic two phase system.545,571... 

S-Captopril (SCpt) (SQ-014534) and R-captopril (RCpt) (SQ-034459) were supplied by Bristol-Myers Squibb Pharmaceutical Research Institute (Princeton, NJ, USA). Novocaptopril tablets (25 mg S-captopril/ tablet) were supplied by Novopharma Ltd., Toronto, Canada. 2-Hydro-xy-3-trimethylammoniopropyl-/1-cyclodextrin was supplied by Wacker-Chemie GmbH (Germany). 

Karakhanov, E. A., Zhuchkova, A. Y., Filippova, T. Y., Maksimov, A. L. Supramolecular cyclodextrin-based catalyst systems in Wacker oxidation. Neftekhimiya 2003,43, 302-307. 

Monflier, E., Tilloy, S., Blouet, E., Barbaux, Y., Mortreux, A. Wacker oxidation of various olefins in the presence of per(2,6-di-0-methyl)-P-cyclodextrin mechanistic investigations of a multistep catalysis in a solvent-free two-phase system. J. Mol. Catal. A Chemical 1996,109, 27-35. 

Wacker oxidation of olefins to ketones catalyzed by palladium complexes is a well-known process which has been applied to numerous olefins [120]. However, selective oxidation of Cg-Cig a-olefins remains a challenge. Recently, Mortreux et al. have developed a new catalytic system for the quantitative and selective oxidation of higher a-olefins in an aqueous medium [121-123]. For example, 1-decene was oxidized to 2-decanone in 98% yield using PdS04/ H9PV6M06O40/CUSO4 as the catalyst in the presence of per(2,6-di-0-methyl)-j9-cyclodextrin, which probably played the role of a reverse phase transfer reagent [Eq. (22)]. 

This catalytic system consisted of an aqueous acidic solution of a palladium salt with a cop-per(I) salt and oxygen or air as an oxidant however, application of the Wacker process to longer chain alkenes has been a challenge due to their low solubility in aqueous media. This has led to research in biphasic systems using tetraalkylammonium salts,93 polyethylene glycols,94 as well as cyclodextrins.95,96... 

Cyclodextrins are included here as water-soluble supports. They will also be mentioned in Chap. 7 on separations and in Chap. 8 on running reactions in water instead of organic solvents. Cyclodextrins221 are made by the enzymatic modification of starch.222 They are made commercially by Cer-estar and Wacker Chemie. They have conical structures of six, seven, and eight glucose units in rings, denoted a- /3-, and y-cyclodextrin, respectively. Mercian Corporation has a process for /3-cyclodextrin, which is more selective than usual, that produces no a- and only a small amount of the y-product.223 The insides are apolar and hydrophobic, whereas the outsides are hydrophilic (Table 5.2). 

The dicarboxylic acid was obtained in 65% yield with 79% selectivity. Fortunately, there are better ways (see Chap. 6) to make this compound without the use of toxic carbon tetrachloride. This method gives 100% selectivity at 71% conversion in the reaction of biphenyl-4-carboxylic acid to form the 4,4 -biphenyldicarboxylic acid. /3-Cyclodextrin accelerates the platinum-catalyzed addition of triethoxysilane to styrene.231 The reaction is 100% complete in 30 min at 50°C with the cyclodextrin, but only 45% complete without it. The Wacker reaction of 1-decene produces several ketones owing to double-bond isomerization. If the reaction is run in a dimethylcyclodextrin, isomerization is reduced by faster reoxidation of palladium(O).232 The product 2-decanone is obtained with 98-99% selectivity (5.57). 

Long-chain aliphatic olefins give only insufficient conversion to the acids due to low solubility and isomerization side reactions. In order to overcome these problems the effect of co-solvents and chemically modified /i-cyclodextrins as additives was investigated for the hydrocarboxylation of 1-decene [23], Without such a promoter, conversion and acid selectivity are low, 10% and 20% respectively. Addition of co-solvents significantly increases conversion, but does not reduce the isomerization. In contrast, the addition of dimethyl-/i-cyclodextrin increased conversion and induced 90% selectivity toward the acids. This effect is rationalized by a host/ guest complex of the cyclic carbohydrate and the olefin which prevents isomerization of the double bond. This pronounced chemoselectivity effect of cyclodextrins is also observed in the hydroformylation and the Wacker oxidation of water-insoluble olefins [24, 25]. More recent studies of the biphasic hydrocarboxylation include the reaction of vinyl aromatic compounds to the isomeric arylpropanoic acids [29, 30], and of small, sparingly water-soluble alkenes such as propene [31]. 

Karakhanov s group has also been exploring poly(ethylene oxide)- and poly(alkene oxide)-copolymer-bound catalysts [99-102]. A notable aspect of this work is the design of polyethers like 39 that contain jS-cyclodextrins and calyx[4]- and calyx[6]arenes. Such polyethers couple the molecular recognition associated with these macrocycles with the catalytic activity of acac, phosphine, dipyridyl, and catechol ligands. Metals complexed to such ligands have been used in reactions like hydroformylation, Wacker oxidations, and arene hy-droxylation. 

The first use of such agents has been reported, almost simultaneously, by Zahalka et al. [36] and Harada et al. [37] they introduced a cyclodextrin into the PdCl2-CuCl2 catalyzed oxidation of terminal alkenes into the corresponding methyl ketones (Wacker-... 

Cyclodextrins are the most used host compounds so far. Native cyclodextrins are effective inverse phase-transfer catalysts for the deoxygenation of allylic alcohols [3], epoxidation [4], oxidation [5], or hydrosilylation [6] of olefins, reduction of a,y9-unsaturated acids [7], a-keto ester [8], conjugated dienes [9] or aryl alkyl ketones [10]. Interestingly, chemically modified cyclodextrins like the partially O-methylated y0-cyclodextrin (RAME-y9-CD) show a better catalytic activity than native cyclodextrins in numerous reactions such as the Wacker oxidation [11], hydrogenation of... 

Complexes with modified cyclodextrins were initially used as models of hydrolytic enzymes [20,181,197,198]. Then, Breslow and Kato studied such complexes in biomimetic oxidation and epoxidation. Reetz and some other researchers investigated them in hydroformylation. We examined cyclodextrin-based catalysts in hydroxylation and Wacker oxidation. Note that some of these studies demonstrated a substantial increase in the activity of the catalysts in comparison with their analogues prepared as ordinary mixtures, which was due to the cooperative substrate binding. 

A palladium complex with cyclodextrin modified with propionitrile and benzoylnitrile groups 73-74 was active in Wacker oxidation of higher 1-alkenes (Experiment 11-4, Section 11.7), and its activity was much higher than the activity of a catalj ic system prepared as a mixture of cyclodextrin and the palladium complex owing to the cooperative substrate binding and to the increase in the stability constant of the catalyst-substrate complex. As in hydroformylation, the catalyst was more active in the reaction with an aromatic substrate, styrene, than with linear alkenes [59,210-211], The catalyst activity depended on the 1-alkene chain length and was maximum for 1-heptene. 

Experiment ll-4 P-Cyclodextrin-Based Pd Complexes in Wacker Oxidation (Section 11.6) [210]... 

Monflier, E. Blouet, E. Barbaux. Y. Mortreux. A. Wacker oxidation of I-decene to 2-decanone in the presence of a chemically modified cyclodextrin system A happy union of host-guest chemistry and homogeneous catalysis. Angew. Chem.. Int. Ed. 1994. 33. 2100-2102. 

Storage 6 mos shelf life store R.T. in sealed containers Cavasol W8 HP [Wacker-Chemie GmbH/Biotech. Wacker Biochem] Chem. Descrip. Hydroxypropyl-T cyclodextrin CAS 128446-34-4... 

CPI Chems. Camida Ltd CarboMer Cerestar USA Cyclodextrin Tech. Development Eastman Fiuka Forum Chems. Pfanstiehl Labs Roquette S.A. Chems. Sigma Spectrum Quality Prods. U.S. Biochemical Univar Ltd Wacker Chems. 

One product made directly by the fermentation of starch, cyclodextrin, is especially interesting as a fermentation product In 1998 the global market was estimated between 1800 and 3600tormes. As stated by the company, Wacker Chemie had at that time a production capacity of 3000 tonnes. Today, 10 years later, they have increased their production capacity to 7500 tonnes of cydodextrins a year. These molecules are used as stabilizers and exdpients in the pharmaceutical, life sdence, cosmetics, food, and agricultural industries. 

Manuf./Distrib. Adept Sol ns. Aldrich http //www.sigma-aldrich.com, AshIand http //www.ashchem.com, Aventis Pharmaceuticals CPI Chems. http //www. cpichem. com Camida Ltd http //www.camida.com, CarboMer http //www.carbomer.com, Cerestar USA Cyclodextrin Tech. Development Eastman http //www. eastman. com Fluka http //www.sigma-aldrich.com. Forum Chems. http //www.forum.co.uk, Pfanstiehl Labs http //www.pfanstiehl.com, Roquette http //www.roquette.fr/eng, S.A. Chems. http //www.sachemicals. com Sigma Spectrum Quality Prods. http //www.spectrumchemical. com, U. S. Biochemical Univar E E Ltd http //www.univar.co.uk, Wacker Chems. 

Trade Name Synonyms Cavasol W7 HP [Wacker-Chemie GmbH/Biotech. http //www.wacker-biochem.com ht //www.wacker-heiicone.com Wacker Biochem http //www.wacker-biochem.com] Cavasol W7 HP Pharma [Wacker-Chemie GmbH/Biotech. http //www.wacker-biochem.com http //www.wack.er-heiicone.com Wacker Biochem http //www.wacker-biochem. com] Encapsin HPB [Janssen Biotech NV] Hydroxypropyl-y-cyclodextrin CAS 99241-25-5 128446-34-4 Properties M.p. 250 C... 

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