Copper trans- 1,4-cyclohexane

Sterically more demanding copper(II) chelates based on trans-cyclohexane-1,2-diamine reveal similar condensation chemistry [165]. The yield of macrocyclic products, however, decreases compared to the reaction with ethane-1,2-diamine-containing chelates. The formation of copper(II) complexes of half-capped ligands is favoured compared to capped species for steric reasons. The presence of two asymmetric carbon atoms in the starting ligson allows synthesis of new chiral macrocycles. The most suitable for macrocyclisation has proved to be the R,R S,S bis(cyclohexane-l,2-diamine)copper(II). The three isomers of H2LI36 possible... 

Finally, when aziridines bear a 2-alkenyl substituent, they can engage in an SN2 reaction with dialkylzinc reagents using copper catalysts. Enantioselectivity can also be induced by including a chiral ligand, such as the binaphthyl phosphoramidite 174. For example, the aziridinyl cyclohexane 175 provided exclusively the trans-, 4 adduct with 83% ee upon treatment with dimethylzinc in the presence of copper(II) triflate and ligand 174 <03TL8559>. 

The first reaction takes place at between 160 and 180 0, under 30 to 40.106 Pa absolute, in the presence of supported palladium. The operation is conducted in solution in the ester formed to prevent excessive temperature rise due to the exothermicity of the reaction. Molar selectivity of the saturated ester exceeds 95 per cent The crude product obtained is sent to a hydrogenolysis reactor, where it is converted to dimethylol cyclohexane and methanol in the presence of copper chromite. The dimethylol cyclohexane obtained contains about 33 per cent of the cis isomer and 76 per cent of the trans isomer. 

Inoue et al. [150] demonstrated that large amounts of carbon tetrachloride can be absorbed into 1-dimensional tunnels in copper(II) trans-1,4-cyclohexane dicarboxylate (Figure 14) under the saturated vapour pressure at room temperature, and the desorption can be performed easily by evacuation above room temperature. It was also confirmed that the absorption/desorption is reversible. The thermodynamic and structural properties were studied for the empty (non-absorbed) sample and partially-filled (10, 22 and 31% of the fiill carbon tetrachloride-absorbed) samples, using adiabatic calorimetry between 13 and 300 K and by powder XRD with high-energy synchrotron radiation. The heat- capacity anomaly due to the first-order phase transition observed in the empty sample was not observed in the fully-absorbed sample. However, the partially absorbed samples showed smaller heat-capacity anomalies at lower temperatures than the empty sample. Such phenomena were compared with the previous results for toluene-absorbed samples [151-153] and tfie differences were discussed. 

Figure 14. Structure of copper(II) trans-1,4-cyclohexane dicarboxylate. Reproduced from reference [151] with permission from Elsevier.

Ca6H620aP2Pd2, sym-trans-Di-/x-acetatobis(o-(t-butyl-o-tolylphos-phino)benzyl)dipalladium(II) cyclohexane solvate, 40B, 868 C4 8H30CU4F18N4O14, Bis(hydroxy-tris(trifluoroacetato)di(quinoline-copper (II))), 40B, 994... 

Rizkov et al. ° used L-and D- 3-amino alcohols for the enantioseparation of, among others, dansylated (Dns) AAs by CZE in a low-molecular-weight organogel (LMOG)-filled capillary. This LMOG is a fibrillar gel of trans-(15,2S)-l,2-bis-(dodecylamido) cyclohexane in MeOH. Bare fused-silica capillaries with an i.d. of 100 fim and a total length of 60.0 cm (52.0 cm effective length) were used. The BGE contained 10-mM 3-amino alcohol and 5-mM cupric acetate monohydrate in MeOH with pH 5. The selector copper-valinol (2 1) performed best compared... 

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