Cyclohexene results

Chiral Alcohols and Lactones. HLAT) has been widely used for stereoselective oxidations of a variety of prochiral diols to lactones on a preparative scale. In most cases pro-(3) hydroxyl is oxidized irrespective of the substituents. The method is apphcable among others to tit-1,2-bis(hydroxymethyl) derivatives of cyclopropane, cyclobutane, cyclohexane, and cyclohexene. Resulting y-lactones are isolated in 68—90% yields and of 100% (164,165). 

The resulting material is active for the gas phase epoxidation of simple olefins. Addition of cyclohexene resulted in the formation of cyclohexene oxide as the sole volatile product, detected by GC/MS. 

The reaction of aryldiazoacetates with cyclohexene is a good example of the influence of steric effects on the chemistry of the donor/acceptor-substituted rhodium carbenoids. The Rh2(reaction with cyclohexene resulted in the formation of a mixture of the cyclopropane and the G-H insertion products. The enantios-electivity of the C-H insertion was high but the diastereoselectivity was very low (Equation (31)). 0 In contrast, the introduction of a silyl group on the cyclohexene, as in 15, totally blocked the cyclopropanation, and, furthermore, added sufficient size differentiation between the two substituents at the methylene site to make the reaction to form 16 proceed with high diastereoselectivity (Equation (32)).90 The allylic C-H insertion is applicable to a wide array of cyclic and acyclic substrates, and even systems capable of achieving high levels of kinetic resolution are known.90... 

The mechanism for the photoreaction between 133 and cyclohexene can be summarized as in Scheme 8. The initiating electron transfer fluorescence quenching of 133 by cyclohexene resulted in the formation of an w-amino radical-radical cation pair 136. Proton transfer from the 2-position of the cyclohexene radical cation to the nitrogen atom of the a-amino radical leads to another radical cation-radical pair 137. Recombination of 137 at the radical site affords the adduct 134, while nucleophilic attack at the cation radical of 136 leads to another radical pair 138 which is the precursor for the adduct 135. 

The cyclic diolefin formed can then dehydrogenate as was discussed previously for this type of compound, and the hydrogen eliminated may be transferred to -methylstyrene, as was previously discussed for phenyl-cyclohexene, resulting in the formation of cumene. The diaryldiolefin shown in this mechanism was synthesized and successfully cyclized to p-terphenyl in the presence of sodium 55). 

The addition of B2C14 to multiple bonds was shown to be stereoselective. The initial diborane products isolated after the addition of B2C14 to cis- and trans-2-butene were oxidized to yield meso- and racemic-2,3-butanediols, respectively.478 480 A similar treatment of the addition product of cyclohexene resulted in cis-1,2-cyclohexanediol 480 These observations are consistent with syn addition and the involvement of four-center transition state 42. Similar studies with addition... 

Proof for the triplet character of the hydrogen abstracting species is obtained in sensitization experiments. Thus, direct photolysis of ethyl azidoformate in cyclohexene results in the formation of only 3% of the hydrogen abstraction product (urethane) and a trace of 6w-cyclo-hexene -. In the sensitized photoreaction, where triplet nitrene is produced directly, the urethane yield increases to 74%, the yield of Aw-cyclohexene to 63%. 

Irradiation of ethyl azidoformate (66) at 2537 A in cyclohexene results in five identifiable products 7-ethoxycarbonyl-7-azabicyclo [4.1.0]-heptane (67) (50%), iV-2-cyclohexenylurethane (68) (9%), JV-3-cyclohexenylurethane (69) (3%), urethane (70) (3%) and bi(cyclohex-2-enyl) (71) (1-7%). Photolysis of ethyl azidoformate... 

The anodic dimethoxylation of simple cyclic olefins, such as cyclohexenes, results in the predominant formation of ra/w-dimethoxycyclohexanes [303,305]. However, Barba and CO workers [306] reported that the stereochemistry of l,2-dimethoxy-l,2-dihydroace-naphthene derived from acenaphthene is drastically influenced by the anode material. Palasz and Utley [307] have reported that jV-acetylpiperidines are methoxylated via the enamide intermediate species formed by the oxidation. 1,3-Dienes are also 1,4-dimethoxylated in low stereoselectivity [293]. The anodic methoxylation of or-pinene proceeds similarly to the acetoxylation, resulting in the formation of two sets of stereoisomeric products [308]. 

This finding of complete transfer of peroxidic oxygens to substrate is consistent with IR spectroscopic evidence (Figure 1). Furthermore, regeneration of the rerr-butylperoxo complex 2 by treatment of 3 with tert-butylhydroperoxide, followed by its subsequent reaction with cyclohexene, resulted in the formation of another four equiv. of cyclohexene oxide, eq 6. Its active sites are therefore not susceptible to deactivation either during or after epoxidation. 

C]-hexene, 1% cyclohexene, 75% cyclohexadiene. Due to the incomplete separation of hexenes and cyclohexene resulted in the appearance of radioactivity as an artifact in the cyclohexene impurity. After Ref. 20. 

Gas chromatography Acesulfame-K, aspartame, cyclamate, saccharin, and stevioside are determined by gas chromatography, but the main drawback of this technique is that a derivatization is required. Acesulfame-K is methylated with ethereal diazomethane, aspartame is converted into its N- 2-methylpropoxycarbonyl) methyl ester derivative, menthol and isobutyl chloroformate are used to convert aspartame to 3-[(isobutoxycarbonyl)amino]-4-[[a-(methoxycarbonyl)phenethyl]amino]-4-oxobutyric acid, cyclamate is determined as cyclohexene resulting from the reaction with nitrite, saccharin is converted to N-methylsaccharin, and stevioside is hydrolyzed. Detection is carried out utilizing flame-ionization, flame-photometric electron-capture detectors or nitrogen-phosphorus detection. 

Next, in order to learn more about the rates of dehydrogenation of cyclohexenes resulting from Diels-Alder reactions between butadiene and olefins, VCH, HCH and MCH were earlier subjected to thermal reactions at 530- 665 C ( ). The main reactions in these cases were reverse Diels-Alder reactions and dehydrogenations. Dehydrogenations which are related to the productions of cyclohexa-diene and benzene homologues were 1 10 in selectivity as compared to that of the reverse Diels-Alder reaction. An interesting observation related to cyclic compound formation is that, in the case of MCH pyrolysis, cyclohexadiene and cyclopentene are formed at almost the same rates as butadiene and propylene. So that, in this case, about 60% of MCH is employed in the formation of cyclic compounds. 

A cyclohexene resulting from the cycloaddition reaction of a diene and a dienophile. 

Trimethylsilylazide (TMSA) has found widespread use for the synthesis of alkyl azides when used either preformedor generated in situ In particular, in the presence of thallium triacetate this reagent reacts with cyclohexene to give the intermediate aziridine (50), which with TFA gives the tran -azido-esters (51). If acetyl chloride is substituted for the TFA then tran5-l-azido-2-chloro-cyclohexene results (Scheme 49). Similarly, tran -l-azido-2-iodocyclohexene is... 

Lu et al. [147] carried out the oxidation of alkenes over a 3D porous MOF with the general formula [Co(bpb)]-3DMF, (bpb is l,4-bis(4 -pyrazolyl)-benzene). Cobalt(II) ions in this structure are organized as one-dimensional (ID) chains through tetrahedral coordination with pyrazolyl nitrogen. It is assumed that the treatment with tert-butyl hydroperoxide transforms Co(II) into Co(III). The addition of cyclohexene results in the formation of tert-butyl-2-cyclohexenyl peroxide with a yield of 83%, but some degradation of the structure of MOFs is observed under these conditions after several catalytic cycles. 

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