Chromium -, chloride, resolution

Chromium(ll), cis-dichlorobis( 1,2-ethanedi-amine)-, chloride, resolution of, 26 24, 27... 

After the resolution of 1-2-chloro-ammino-diethylenediamino-cobaltie chloride many analogous resolutions of optically active compounds of octahedral symmetry were carried out, and active isomers of substances containing central cobalt, chromium, platinum, rhodium, iron atoms are known. The asymmetry is not confined to ammines alone, but is found in salts of complex type for example, potassium tri-oxalato-chromium, [Cr(Ca04)3]K3, exists in two optically active forms. These forms were separated by Werner2 by means of the base strychnine. More than forty series of compounds possessing octahedral symmetry have been proved to exist in optically active forms, so that the spatial configuration for co-ordination number six is firmly established. 

AMMONIUM l(lR)-(ElWDO, /[Pg.24]

RESOLUTION OF TRIS (ETHYLENEDIAMINE) -RHODIUM (IU) AND -CHROMIUM (III) CHLORIDE BY MEANS OF (+)-TARTRATE... 

Methods for the preparation of tris(ethylenediamine)rhodium-(III) chloride hydrate and for its resolution by means of the diastereoisomer Ii (—)D-lRh(en)s] (- -)-tart 2 3H20 are presented. The resolution of tris(ethylenediamine)chromium(III) chloride by means of an analogous diastereoisomeric compound is also described. 

The tris(ethylenediamine) chromium (III) ion was first resolved by Werner6 by means of sodium 3-nitro-(+)-camphor. What has been said concerning the resolution of the corresponding rhodium compound holds true of the chromium compound, except that for the chromium compound the solubility difference of the diastereoisomeric chloride (+)-tartrates is so small that a resolution via these diastereoisomers has not been achieved.5,6 The method reported here is essentially the same as the one described for the rhodium complex but with minor alterations... 

Chromium(salen) catalysts are excellent reagents for the desymmetrization of OT to-epoxides. Thus, tfr-stilbene oxide is converted to the (3, 3 )-aminoalcohol in the presence of catalytic quantities of chromium-salen complex in methylene chloride solution open to the atmosphere. The addition of small quantities of triethylamine was found to dramatically increase enantioselectivities (by almost 25%). This catalytic system also promotes an efficient aminolytic kinetic resolution (AKR) of racemic epoxides with 2-type symmetry (Equation 18) <20040L2173, 1999TL7303>. W fo-Epoxides can be opened with aromatic amines in water in the presence of 1 mol% of an Sc(ni) catalyst ligated to 1.2mol% of a chiral bipyridine ligand <2005OL4593>. 

N4Cl2WC2i,H22, Tungsten(VI), (2,2 -bipyri-dine)dichloro[( 1,1-dimethylethyl)-imido](phenylimido)-, 27 303 N4Cl3CrC4Hi , Chromium(III), dichlorobis-(1,2-ethanediamine)-, A-cis-, chloride, and monohydrate, resolution of, 26 24, 27, 28... 

Resolution, of cts-dichlorobis(l,2-ethanedi-amine)chromium(III) chloride, 26 24 of (a corbato(2 - )-C%0 ]( 1,2-cyclohex-anediamine)platinum(II), 27 283 Rhenate(IV), hexaiodo. dipotassium, 27 294... 

CrQ3N4C4H,4, Chromium(III), dichlorobis-(1,2-ethranediamineK A-cis-, chloride, and monohydrate resolution of,... 

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