Copper complexes isomers

Then, as described in U.S. Patent 3,158,648, the optical isomers may be resolved as follows. 37 g of racemic a-methYl-3,4-dihYdroxYphenylalanine are slurried at 35°C in 100 cc of 1.0 N hydrochloric acid. The excess solids are filtered leaving a saturated solution containing 34.6 g of racemic amino acid of which about 61% is present as the hydrochloride. The solution Is then seeded at 35°C with 7 g of hydrated L-o -methYl-3,4-dihYdroxYphenYlalanine (6.2 g of anhydrous material). The mixture is then cooled to 20°C in 30 minutes and aged one hour at 20°C. The separated material Is isolated by filtration, washed twice with 10 cc of cold water and dried in vacuo. The yield of product is 14.1 g of L-a-methYl-3,4-di-hydroxyphenylalanine in the form of a sesquihydrate of 100% purity as determined by the rotation of the copper complex. 

When a copper complex of 83 is used as the catalyst, the reaction can also proceed with excellent selectivity (98% de and >98% ee for the enJo-isomer).30 Note that 83 is similar to 81, but in this compound the two phenyl groups are replaced by two t-butyl groups. 

The 0-, M- and P-Toluidino-Diazido-Copper Complexes. (N3)2Cu.C7H7NH2 mw 254.78 N 38.49% grn-brn cryst mp, ortho-123° (explds), meta- 157-60°(explds), para- 135° (explds). Sol in ethylenediamine and acids. Prepn is by reacting Cu(II) azide with the appropriate toluidine isomer. The isomers have an impact sensy of 10cm, using a 1-kg wt Refs 1) Beil, not found 2) Gmelin, Syst Nr 60, Teil B, Lieferung 1 (1958) 3) A. Cirulis... 

Most reported phthalocyanine derivatives (sulfo-, nitro-, amino-, triphenylmethyl-, polymeric, etc.) are copper complexes, although at present the synthetic chemistry of other d- and /-metal Pc derivatives is being rapidly developed (Examples 30-36) [5,6,116-118]. Some of them (in particular, copper phthalocyanine sulfonic acids) are of industrial interest because of their usefulness as dyes. Phthalocyanine sulfonic acids themselves are prepared both by urea synthesis from sulfonated phthalic anhydride and by the sulfonation of the phthalocyanine [6], Some substituted metal phthalocyanines can be obtained by chemical or electrochemical reduction [118e]. Among a number of reported peculiarities of substituted phthalocyanines, the existence of three electronic isomers for magnesium derivative PcMn was recently confirmed [118f]. 

Kaim W, Wanner M, Knodler A, Zalis S (2002) Copper complexes with non-innocent ligands probing CuVcate-cholato-CuVo-semiquinolato isomer equilibria with EPR spectroscopy. Inorg Chim Acta 337 163-172... 

Tetrakis(L)copper(I) or Silver (I) Perchlorate prom Isomers A AND B. To a suspension of 0.7 g. (4 mmoles) of isomer A or B in 25 ml. of acetone was added 1 mmole of copper(II) perchlorate hexahydrate or anhydrous silver(I) perchlorate, and the suspension was stirred for 18 hrs. The colorless copper complex was filtered off and dried under vacuum at room temperature. Some reduction to silver metal occurred in the reaction of silver perchlorate. The precipitate was therefore extracted with ethanol, and the extract was filtered and concentrated to obtain the complex. Approximately 30% yields of both compounds were obtained. 

X = Me, Ph) are in dynamic equilibrium with their unusual isomers (200). Gold and copper complexes of both types (X = Cp) are now known (201). 

When phosphane-free nickel complexes, such as bis(cycloocta-l,5-diene)nickel(0) or te-tracarbonylnickel, are employed in the codimerization reaction of acrylic esters, the codimer arising from [2-1-1] addition to the electron-deficient double bond is the main product. The exo-isomer is the only product in these cyclopropanation reactions. This is opposite to the carbene and carbenoid addition reactions to alkenes catalyzed by copper complexes (see previous section) where the thermodynamically less favored e Jo-isomers are formed. This finding indicates that the reaction proceeds via organonickel intermediates rather than carbenoids or carbenes. The introduction of alkyl substituents in the /I-position of the electron-deficient alkenes favors isomerization and/or homo-cyclodimerization of the cyclopropenes. Thus, with methyl crotonate and 3,3-diphenylcyclopropene only 16% of the corresponding ethenylcyc-lopropane was obtained. Methyl 3,3-dimethylacrylate does not react at all with 3,3-dimethyl-cyclopropene, so that the methylester of tra 5-chrysanthemic acid cannot be prepared in this way. This reactivity pattern can be rationalized in terms of a different tendency of the alkenes to coordinate to nickel(O). This tendency decreases in the order un-, mono- < di-< tri- < tet-... 

The oldest syntheses of chrysanthemates are those starting from 2,5-dimethyl-2,4-hexadiene (238). There have been more papers on the use of rhodium or antimony to catalyze the addition of diazoacetate and chiral copper complexes to create asymmetry during the addition (see Vol. 4, p. 482, Refs. 219-222). The problem with this route is to avoid the use of diazo compounds. An old synthesis of Corey and Jautelat used the ylide addition of a sulfurane to a suitable precursor (in this case a C3 unit was added to methyl 5-methyl-2,4-hexadienoate, 239), and a recent paper gives details about the addition of ethyl dimethylsulfuranylideneacetate to 2,5-dimethyl-4-hexen-3-one (240). This led exclusively to the tran -isomer 241, from which ethyl trans-chrysanthemate (185, R = Et) was made. Other ylide additions are mentioned below. 

The binuclear copper complex 4 is also an effective catalyst for enantioselective cyclo-propanation of simple olefins76. The major tram-isomer is produced by the -enantiomer of 4 with predominant (15) configuration. For these reactions the influence of the menthyl ester chirality is not negligible otherwise the relatively high difference in the ee values when the R-or S-catalyst is used cannot be rationalized. Thus, double stereodifferentiation seems to operate to some extent. 

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