Trans-1,2-Cyclohexane diol

Specific recognition and assembly instructions for the synthesis of supraminols are encoded also in other chiral diamines, as in the case of (i ,i )-2,3-diaminobu-tane (39) [60], Equimolar amounts of (R,R)-39 and (R,R)-trans- 1,2-cyclohexane-diol (31) self-assemble into a helicate 39 31 (Scheme 17). This structure is characterized by a right-handed helical ribbon core and a left-handed helical strand motif that appears to be more compressed in the a-c plane and more extended along the b plane compared with that previously described for the complex between (R,R)-trans- 1,2-diaminocyclohexane and (i ,i )-2,3-butanediol (Figure 44) [51]. 

A complete study concerning a new class of supramolecular structures (supraminols) has been recently published. These supramolecular structures are formed by an enantiodifferentiating self-assembly between (If , 2f )-diaminocyclohexane and various trans-1,2-cyclohexane diols. An example is shown in eq 27. When racemic diols were used, a homochiral cristalline adduct is formed with an efficient kinetic resolution. 

Even when two related molecules are coencapsulated, unexpected results can emerge. We encountered these initially as complexes within complexes as shown in Fig. 7.17. The benzoic acid and pyiidone dimers are isolated in the capsule, protected from exchange of partners from the bulk solution, and are held in contact by hydrogen bonding. The trans cyclohexane diols, when given the choice, are in a more stable arrangement when one molecule and its mirror image occupy the capsule, rather than two identical molecules. 

Fig. 7.17 Complexes within complexes. Top Two molecules of benzoic acid or pyridone are encapsulated as their hydrogen-bonded dimers. Bottom When trans cyclohexane diol is encapsulated, one molecule and its mirror image are preferred but 2-bromo-butyric acid prefers the complex with two identical molecules inside...

Retardation by acetic acid itself, which reduces the oxidation rate of trans-cyclohexane-1 2-diol by three orders of magnitude, suggests the existence of a pre-equilibrium... 

In connection with our own work on the enzyme-catalysed hydrolysis of cyclohexene epoxide with various fungi we made the unexpected observation that the microorganism Corynesporia casssiicola DSM 62475 was able to interconvert the (1R,2R) and (1S,2S) enantiomers of the product, trans cyclohexan-1,2-dioI 25. As the reaction proceeded the (1R,2R) enantiomer was converted to the (1S,2S) enantiomer [20]. If the racemic trans diol 25 was incubated with the growing fungus over 5 days, optically pure (> 99 % e. e.) (1 S,2S) diol 25 could be isolated in 85% yield. Similarly biotransformation of cis (meso) cycIohexan-1,2-diol 26 yielded the (1S,2S) diol 25 in 41 % (unoptimized) yield (Scheme 11). 

Preparation of the Cyclic Sulfite of trans-Cyclohexane-l,2-diol [14]... 

Trans-Cyclohexane - 1,2 diol Dinitrate, pltlts (from- hot ligroin), mp 18-5 - l9°j impact test value 72-85 cm fumes at 1.65°, ignites at 185°5 Bergmann-Junk test 0.67 mg NO evolved/ lg sample Refs 1) Beil —not found 2) W.R. Christian ... 

Periodic add (or sodium metaperiodate) is often the reagent of choice when the substrate is soluble in an aqueous medium, as in the carbohydrate field an example of its use is to be found in Expt 5.117. Sodium metaperiodate supported on silica gel (Section 4.2.55, p. 454) has been found to effectively oxidise water-insoluble a-diols,106 and its value is illustrated in the preparation of hexanedial (Expt 5.78) from trans-cyclohexane-l,2-diol. 

Ti-MMM with a mesopore diameter of 3.4-3.8 nm showed fairly good activity in cyclohexene oxidation with HP in acetonitrile [35f, g]. Cyclohexene oxide and trans-cyclohexane-l,2-diol prevailed among the oxidation products. No titanium leaching... 

TABLE 4. Comparison of geometries of various derivatives of trans-cyclohexane-l,2-diol (52)... 

Figure 3.6.2 At first a steroid is covalently bound to a gold subphase, then the remaining gaps are filled with octadecyl-thiol. A closed membrane is thus formed with 6 x 14 A gaps caused by the steroidal bottom. The gold electrode is then submersed in an aqueous ferricyanide solution, and a strong cyclovoltammetric signal is observed. Upon addition of molecules that fit into the immobile water structure within the hydrophobic gap (= hydrophobic water), the ion flow is blocked. tran -Cyclohexanediol with two equatorial hydroxy groups is optimal glucose and rhamnose also work. cw-Cyclohexane diol with an axial OH group is much less efficient. The entrapped molecules do not equlibrate with the bulk water. Only upon acidification with HCl to pH < 3 are the entrapped molecules released. (From Fuhrhop et al., 1997.)...

The dehydration of 1,4-cyclohexane diols emphasises the critical importance of stereochemical arrangement of the hydroxy functions in a substrate . The m-diol eliminates to give the cyclohexenol as the major product but the trans isomer yields mainly 1,4-epoxycyclohexane. As elimination from trans-1,4-cyclohexanediol occurs more rapidly than from t-butyl alcohol, anchimeric assistance was suggested, the intramolecular concerted ring closure occurring through a boat conformation, viz. 

Transglucosylation, using different enzymes, from maltose and cellobiose to the enantiomers of trans-cyclohexane-l,2-diol gave stereochemically discrete a- and jS-monoglycosides. 

Starting from racemic trans-cyclohexan-l,2-diol by sequential KR [124]. 

Figure 3.12 Gas chromatograms of hydrolysates of (a) silyl derivative of polyethylene terephthalate, (b) silyl derivative of ethylene glycol 1,4 butane diol and trans isomers of 1,4 cyclohexane diol dimethanol and (c) silyl derivative of iso- phthalic and terephthalic acids derived from a polyester. Reproduced with permission from B.J. Allen, G.M. Elser, K.P. Keller and H.D. Kinder, Analytical Chemistry, 1977, 49, 741. 1977, ACS...

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