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The melting point phase diagram of the (R, R) and (S, S) enantiomeric forms of trans -1,2-cyclohexanediol was constructed. The diagram shows immiscibility of the two enantiomeric forms when the mole fraction of one of the isomers present is above 0.8. For intermediate compositions a solid solution is obtained. The presence of metastable forms is also shown in the diagram.

3-(N-Methylamino)cyclohexane-1,2-diols (RS,RS,RS)-25 and (1RS,2RS,3SR)-26 were synthesised and their crystal structures were studied by X-ray diffraction. Compound 25 co-crystallizes with chloroform in the orthorhombic space group Pna2 1 with cell parameters of a = 11.8550(2) Å, b = 19.8293(4) Å, c = 10.6163(2) Å, V = 2495.64(8) Å3 and Z = 8. Compound 26 crystallizes in the triclinic space group P-1 with cell parameters of a = 13.1019(3) Å, b = 15.0122(3) Å, c = 18.5562(5) Å, α = 95.3082(8), β = 90.3738(10), γ = 115.2775(9), V = 3281.87(14) Å3 and Z = 16. Both structures were characterised by arrays of hydrogen bonding interactions. Graphical Abstract: (RS,RS,RS)-3-(N-Methylamino)cyclohexane-1,2-diol and (1RS,2RS,3SR)-3-(N- Methylamino)cyclohexane-1,2-diol were synthesised and their structures were studied by X-ray diffraction.[Figure not available: see fulltext.] © 2013 Springer Science+Business Media New York.

The study of trans- and cis-1,2-cyclohexanediol by infrared spectroscopy was performed. The variation of the maximum frequency and of the bandwidth of the OH stretching vibration give evidence of the role played by hydrogen bonding in the solid and liquid phases of both isomers and allows to follow the phase transitions. A solid rotator phase is shown for the cis compound.

Mixed monolayers made of steroid thiol molecules lying flat on the surface and thin octadecanethiol walls have been prepared on gold by subsequent chemisorption and self-assembly procedures. Cyclov...

The design and synthesis of chiral crown ethers possessing a chiral recognition ability which carry great potential for separation of enantiomers and analytical purpose has become an important and rapidly growing field of host-guest chemistry. One of the advantages of crown ethers constructed using a synthetic chiral building block is that it is rather easy to modify the chiral cavity resulting in the improvement in enantiomer selectivity. Cyclohexane-1,2-diol derivatives such as cis -1-phenylcyclohexane-1,2-diol, trans -1-phenylcyclohexane-1,2-diol and trans - 1,2-diphenylcyclohexane-1,2-diol are of interest as chiral building blocks of crown ethers, because incorporation of these subunits into the 18-crown-6 framework causes a reduction in conformational flexibility of the chiral cavity and fixes the phenyl chiral barrier perpendicularly above the face of crown ring to modify enantiomer recognition ability. Chiral crown ethers of the 18-crown-6 type were synthesized using these building blocks and their chiral recognition behaviour in differential enantiomer transport through bulk liquid membranes were examined. Chiral azophenolic crown ethers containing cis -1-phenylcyclohexane-1,2-diol or cis -cyclohexane-1,2-diol which can bind neutral amines to form a stable complex and exhibit enantiorecognitive coloration in complexation with chiral amines were prepared and the association constants for their complexes with chiral ethylamine and ethanolamine derivatives were determined on the basis of UV-visible absorbance. The observed enantioselectivity is rationalized in terms of complementarity between a host and a guest as indicated by CPK molecular model examination. The alternation of the position of chiral barriers resulted in a reversal of the enantioselectivity. Crown ethers with diastereotopic faces can bind a guest to each side of the diastereotopic faces to form diastereoisomeric complexes which occasionally cause troublesome “sidedness” problems. In order to avoid the problems, most crown ethers previously prepared contained at least one C 2 axis of symmetry. However, diastereotopic face selectivity in complexation does provide helpful information on the complexing behaviour of crown ethers to assist in the design of more elaborate and structured host molecules. meso -Crown ethers having cis-1-phenylcyclohexane-1,2-diol were prepared and the diastereotopic face selectivity by their diastereotopic faces in complexation with achiral amines was examined by temperature-dependent 1H nuclear magnetic resonance. Ethanolamine is attached stereoselectively to one of the faces to give one of diastereoisomeric complexes and the alternation of the position of steric barriers led to reversal of the diastereotopic face selectivity. A prediction of which diastereoisomeric complex is formed is made on the basis of CPK molecular model.

(±)-trans and cis Cyclohexane-1,2-diols have been shown to undergo a double stereoinversion process to give trans (S,S)-cyclohexane-1,2-diols on incubation with the fungus C. cassiicola.

Ruthenium complex-catalyzed N-heterocyclization of 2-aminopyridines with vicinal-diols offers a novel synthetic method for various imidazo[1,2-a]pyridines. For example, the reaction of 2-amino-4-methylpyridine with 1,2-cyclohexanediol in the presence of a catalytic amount of RuCl2(PPh3)3 under reflux in diglyme for 24 h afforded 2-methyl-6,7,8,9-tetrahydropyrido[1,2-a]benzimidazole in 74% yield.

Diastereoselective elimination of syn- and anti-1 under basic condition, and subsequent protection of the hydroxy group followed by acid hydrolysis of the enol ether function gave (1S,2R)-3 of 72% e.e.

When hydroxyl groups are derivatized to apply the CD exciton chirality method, the absorption maxima of introduced chromophores should not overlap with that of the substrate, except for cases in which the coupling between the existing and the introduced chromophores are deliberately sought for. Thus, the availability of red-shifted chromophores that do not overlap with the substrate absorption would greatly expand the applicability of this versatile CD method. Four such red-shifted chromophores, chrom-II, -III, -IV, and -V, have been developed to convert hydroxyl groups into esters that absorb strongly in the range 360-410 nm. Using the chromophoric triazole amide, they can readily derivatize hydroxyl groups of the substrates on a microscale. The bischromophoric esters of 1(R),2(R)-cyclohexanediol exhibited intense exciton-split CD curves with the signs correctly representing the absolute sense of twist between the two hydroxyl groups. The 1,2-diol moieties of taxinine and chromomycin A 3 derivatives, already having strong absorptions at 260-275 nm, were esterified with the new chromophores; this gave rise to strong couplets isolated from the CD Cotton effects of starting materials, the signs of which were in agreement with the absolute configurations and conformations of chiral substrates, including biopolymers; they could also be conveniently used in conjunction with the red-shifted chromophores developed recently for primary amino groups

Diastereoselective elimination of syn- and anti-1 under basic condition, and subsequent protection of the hydroxy group followed by acid hydrolysis of the enol ether function gave (1S,2R)-3 of 72% e.e.

The design and synthesis of chiral crown ethers possessing a chiral recognition ability which carry great potential for separation of enantiomers and analytical purpose has become an important and rapidly growing field of host-guest chemistry. One of the advantages of crown ethers constructed using a synthetic chiral building block is that it is rather easy to modify the chiral cavity resulting in the improvement in enantiomer selectivity. Cyclohexane-1,2-diol derivatives such as cis -1-phenylcyclohexane-1,2-diol, trans -1-phenylcyclohexane-1,2-diol and trans - 1,2-diphenylcyclohexane-1,2-diol are of interest as chiral building blocks of crown ethers, because incorporation of these subunits into the 18-crown-6 framework causes a reduction in conformational flexibility of the chiral cavity and fixes the phenyl chiral barrier perpendicularly above the face of crown ring to modify enantiomer recognition ability. Chiral crown ethers of the 18-crown-6 type were synthesized using these building blocks and their chiral recognition behaviour in differential enantiomer transport through bulk liquid membranes were examined. Chiral azophenolic crown ethers containing cis -1-phenylcyclohexane-1,2-diol or cis -cyclohexane-1,2-diol which can bind neutral amines to form a stable complex and exhibit enantiorecognitive coloration in complexation with chiral amines were prepared and the association constants for their complexes with chiral ethylamine and ethanolamine derivatives were determined on the basis of UV-visible absorbance. The observed enantioselectivity is rationalized in terms of complementarity between a host and a guest as indicated by CPK molecular model examination. The alternation of the position of chiral barriers resulted in a reversal of the enantioselectivity. Crown ethers with diastereotopic faces can bind a guest to each side of the diastereotopic faces to form diastereoisomeric complexes which occasionally cause troublesome “sidedness” problems. In order to avoid the problems, most crown ethers previously prepared contained at least one C 2 axis of symmetry. However, diastereotopic face selectivity in complexation does provide helpful information on the complexing behaviour of crown ethers to assist in the design of more elaborate and structured host molecules. meso -Crown ethers having cis-1-phenylcyclohexane-1,2-diol were prepared and the diastereotopic face selectivity by their diastereotopic faces in complexation with achiral amines was examined by temperature-dependent 1H nuclear magnetic resonance. Ethanolamine is attached stereoselectively to one of the faces to give one of diastereoisomeric complexes and the alternation of the position of steric barriers led to reversal of the diastereotopic face selectivity. A prediction of which diastereoisomeric complex is formed is made on the basis of CPK molecular model.

epoxy alcohols are regio and chemoselectively opened to the corresponding iodohydrins and then reduced in situ to diols; the application of the described procedure leads to a short asymmetric of a well known pheromone. Also homoallylic (E and Z) epoxy alcohols and its benzylated derivatives shows high preference for regioselective opening affording the corresponding 1,3 diol.

It is well known that cis-cyclohexane-1,2-diol and its mirror image are not superposable, but that these isomers are rapidly interconvertible by flipping from one chair conformation to the other. That is they exist as a pair of conformational enantiomers. Two aldehydes, 2-[8-(4-methylpent-3-enyl)-7,9-dioxabicyclononan-8-yl]ethanals, with the cis-cyclohexane-1,2-dioxy function at C(3) are cyclized by a RhI(Wilkinson) complex to give two conformational diastereoisomers due to the cyclohexane-1,2-diol moiety. Each conformational diastereoisomer of the title compound's parent alcohol yielded trans-3-hydroxy-4-isopropenylcyclohexanone and cis-cyclohexane-1,2-diol after deprotection with 5% aq. AcOH. Unambiguous stereochemistry of two of the parent alcohols was determined by X-ray crystallographic analysis of their p-bromobenzoates. The stereochemistry of the 1,3-dioxolane ring, including C(1) and C(2) of the cis-cyclohexane-1,2-diol and C(1′) of the trans-3-hydroxy-4-isopropenylcyclohexanone, was C(1′)-axial-O-axial-C(1) and C(1′)–equatorial–O–equatorial–C(2) for the two title compounds, and C(1′)-axial-O-equatorial-C(1) and C(1′)–equatorial-O–axial–C (2) for the other pair of isomers.

Vibrational circular dichroism (VCD) of the OH stretching vibrations in intramolecular hydrogen bond systems, i.e. 1,2-diols and β-methoxyalcohols, has been studied. The VCD feature of the OH stretching mode is discussed in relation to the molecular conformation, with the aid of the results of 1H NMR spectroscopy. The positive VCD observed for the OH stretching vibration of the donor hydroxyl group in intramolecular hydrogen bond systems is attributable to the G− conformation about the O C C O bond. The rotational strengths calculated on the basis of the dynamic polarization model account for the observed VCD feature.

Heat capacities of cis-1,2-cyclohexanediol and trans-1,2-cyclohexanediol enantiomers have been determined in the solid state in the temperature range T = (173 to 368) K for the cis-isomer and T = (173 to 373) K in the case of the trans-isomer and in the liquid state at temperatures up to 428 K. Measurements were carried out by differential scanning calorimetry using the enthalpic method. For the cis-isomer, the results show that, before the liquid state is reached, a highly disordered phase is formed. The trans-enantiomers show only a one-step fusion process. The values obtained for the solids are quite well predicted by Goodman’s power law group contribution method, except for the lower temperatures. The Ružicka method was tested for the prediction of liquid state heat capacity values giving results (15 to 20) % lower than the experimental values.

A polyaza cleft was synthesized and shown to bind 1,2- and 1,3-cyclohexanediols and 1,3-2-cyclohexanetriol in chloroform.

Asymmetric ring cleavage reaction of meso -carbobicyclic ketones by a combination of benzaldehyde, chiral cycloalkane-1,2-diol, and Lewis acid gave optically active styrenyl esters of 26–69% ee in moderate yield. The ring cleavage reaction could be applied to the construction of adjacent chiral quaternary carbons, and also to the formal synthesis of natural alkaloid (−)-alloyohimbane.

3,4-Di-O-benzyl-2,6-dideoxy-L-arabino-hexono-1,5-lactone (1b) was synthesized in three steps by starting from di-O-acetyl-L-rhamnal (6). Sequential treatment of 1b or 3,4,6-tri-O-benzyl-2-deoxy-D-arabino-hexono-1,5-lactone (1a) with triethyloxonium tetrafluoroborate and sodium ethanolate produced the diethyl ortholactones 2a and b. Acid-catalyzed reaction of 2a or b with 1,2-ethanediol (5a) or (1S,2S)-1,2-cyclohexanediol (5b) gave the spiro ortholactones 3a, b, and 4a, b.

By employing either dimethyldioxirane or its trifluoromethyl analog, the direct, high-yield conversion of one cyclic and three open chain optically sec,sec-1,2-diols to the corresponding α-hydroxy ketones in high optical yield has been achieved

The positions of the equilibria between the diequatorial and diaxial conformers of trans-1,2-dimethoxycyclohexane (2) and trans-2-methoxycyclohexanol (3) have been measured accurately by 13C n.m.r. spectroscopy at -80°C in a series of solvents ranging from non-polar pentane to highly polar methanol. The equilibria favour the diequatorial conformers under all conditions but the extent increases with solvent polarity and is greater for (3). Improved parameters for the OCCO torsional term in MM3 (94) have been developed (V1, V2, and V3, 3.0, -2.5, 1.25, respectively) by comparison with conformational data for (2) and 1,2-dimethoxyethane (1). Application of the modified parameters to a number of examples demonstrates marked improvement for ethers. These examples include 1,2-dimethoxypropane, for which n.m.r. spectra in (D12) cyclohexane have been analysed and those from the gas phase reevaluated. Lesser improvement was achieved for systems having intramolecular hydrogen bonding. Ab initio results for rotation about the C 5-C 6 bond in pyranosides are satisfactorily reproduced but experimental results favour the gg and tg rotamers over the tg rotamer considerably more than calculated.

Chiral tricyclic α,β-unsaturated lactones (6a,b and 8a,b) were easily synthesized from chiral cyclic diols (2-4) and cyclic β-keto esters (1a,b). Alkylation of 8b proceeded in a highly diastereoselective manner to afford a quaternary carbon

Novel asymmetric spirocyclization of 3-(4-oxopentyl)cyclohex-2-en-1-one 3 based on activation of carbonyl function by BF3-(S,S)-cyclohexane-1,2-diol system has been studied to afford the C2-symmetric dione (–)-5 of 85% enantiomeric excess (e.e.) in 86% yield.

The cyclohexane-1,2-diol derivatives 1 and 4 of high optical purity have been prepared by enantioselective hydrolysis of their acetates (±)-2 and (±)-5 using pig liver esterase. The enantiomer recognition behaviour of the chiral crown ethers 11, 14, 15 and 16 containing the cyclohexane-1,2-diol derivatives as a chiral subunit has also been examined.

Biologically active 4-text-butyl-1-methyl-3,3,4,5,5-pentadeuterocyclohexane-1c,2c-diol and cis-2-phenyltetrahydropyran-5-ol have been prepared in the solid state, recrystallized and identified. Extensive measurements have been carried out on these materials comprising infrared; electronic absorption spectra before, and after exposure to an absorbed energetic, γ-ray dose (107 rd). These materials were chosen as they have intramolecular hydrogen bonding of variant origin. The relative strength of hydrogen bonding and magnitude of γ-radiation damage were evaluated in each case. Results obtained were in conformity, explained, assigned and discussed in details in relation with the nature and origin of hydrogen bonding in each case.

ESR measurements were carried out on the samples of electron‐irradiated cyclohexanediols. In the case of 1,2‐diols, the results are consistent with an interpretation of trapping of two conformationally isomeric radicals, cis‐ and trans‐cyclohexane−1,2‐diol−1, at −196°C and their intramolecular conversion to cyclohexanone−2 or 2‐hydroxycyclohexanone−6 radicals upon warming to room temperature.

A number of optically active cyclohexanol and cyclohexane-1,2-diol derivatives, chiral auxiliaries and substitutes for (–)- and (+)-8-phenylmenthol, have been prepared by enzymatic hydrolysis of their racemic acetates and chloroacetates in the presence of highly selective ester hydrolase from Pseudomonas sp.(SAM–II).

Both enantiomers of the azophenolic crown ether 1 incorporating the cis-cyclohexane-1,2-diol residue as the chiral centre have been prepared in enantiomerically pure forms and the chiral recognition behaviour towards 2-aminoethanols and ethylamines has been examined. The observed enantiomer selectivities of the crown ether 1 in complexation with racemic amines have been interpreted on the basis of CPK molecular model examination of the diastereoisomeric complexes.

Preparations are described of (+)-trans,anti,trans-dicyclohexyl-18-crown-6(2), (+)-trans-cyclohexyl-15-crown-5 (5), and (+)-trans-cyclohexyl-18-crown-6 (6) from (+)-trans-cyclohexane-1,2-diol. Each of the crown ethers was converted into a typical cryptate.