Cyclohexane derivatives nitrones

Inositols and Other Cyclohexane Derivatives - The isoxazolidinocarbocyclic derivative 89 has been produced together with a five-membered carbocyclic compound (diagram 72 in Section 2.1) by cycloaddition from nitrone 73. The formation of 89 predominated in polar protic solvents whilst the reverse was observed in non polar and polar aprotic solvents. 

Intramolecular nitroaldol reactions are a useful choice for the conversion of sugars into polyhydroxylated nitro cyclopentanes, nitro cyclohexanes and their derivatives.46 Baer et al. in the course of their studies on the cyclization of 6-deoxy-6-nitrohexoses under kinetic and thermodynamic control,47 established the reaction pathway involved in the formation of nitroinositols mediated by intramolecular Henry reactions. Firstly, a nitronate is formed and then, under thermodynamic control conditions, an epimerization occurs before cyclization. But, under kinetic controlled conditions, the cyclization occurs first.48... 

Nitro-compounds fRNOj) are isomeric with nitrites, but their electronic structure, excited states and photochemistry are very different. There is no very low-lying (n.jt ) state, and nitroalkanes show n — 3i absorption with a maximum around 275 nm ( —201 mol - cm In cyclohexane solution, nitromethane (CH1NOi) is photoreduced to nitrosomethane(CH,NO, but nitroethane under the same conditions gives rise to a nitroso-dimer derived from the solvent CS.47). The latter process is probably initiated by cleavage of the carbon-nitrogen bond in the nitroalkane. In basic solution (when the nitroalkane is converted to a nitronate anion) irradiation can lead to efficient formation of a hydroxamic acid (S.48), and this reaction most likely proceeds through formation of an intermediate three-mem bered cyclic species. 

Under photo-stimulation, isoindolyloxyl radical (5) abstracts primary, secondary, or tertiary hydrogens from unactivated hydrocarbons including cyclohexane, isobutane, or n-butane (Scheme l).23 The nitroxide (5) traps the resultant carbon-centred radical (R ) and so afford the A -aI koxyisoindo les (6). Blank photolysis experiments with no added hydrocarbon have shown some unprecedented / -fragmentation of (5) to afford the nitrone (7). A number of C60 nitroxide derivatives have been synthesized and characterized by ESR spectroscopy which show features common to nitroxide radicals.24 Reaction of nitroxide and thionitroxide radicals with thiyl radicals have been observed, from which sulfinyl, sulfonyl, and sulfonyloxy radicals were generated.25 The diisopropyl nitroxide radical was generated in the reaction of lithium diisopropylamide with a-fluoroacetate esters.26... 

The total synthesis of (+)-cyclophellitol containing a fully oxygenated cyclohexane ring was accomplished by T. Ishikawa and co-workers. The synthetic strategy was based on the intramolecular silyl nitronate [3+2] cycloaddition reaction. The cycloaddition precursor was prepared by the Henry reaction starting from a D-glucose-derived aldehyde. 

Cyclopentane Derivatives - The isoxazolidinocarbocyclic derivative 72 was produced (together with a six-membered compound (89)-see Section 2.2) from cyclization of the nitrone 73, itself generated in situ from the iV-benzylhydroxyl-amine derivative of 3-C-allyl-l,2-0-isopropylidene-a-D-riZw>-pentodialdofuranose. The formation of the cyclopentane adduct predominated in non polar and polar aprotic solvents while the cyclohexane adduct predominated in polar protic solvents. ... 

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