Cyclohexene hydrogenation effect

An example of this reaction is the reaction of cyclohexene with t-butyl perbenzoate, which is mediated by Cu(I). " The initial step is the reductive cleavage of the perester. The t-butoxy radical then abstracts hydrogen from cyclohexene to give an allylic radical. The radical is oxidized by Cu(II) to the carbocation, which captures benzoate ion. The net effect is an allylic oxidation. 

Solvents influence rate as well as selectivity. The effect on rate can be very great, and a number of factors contribute to it. In closely related solvents, the rate may be directly proportional to the solubility of hydrogen in the solvent, as was shown to be the case for the hydrogenation of cyclohexene over platinum-on-alumina in cyclohexane, methylcyclohexane, and octane 48). Solvents can compete for catalyst sites with the reacting substrates, change viscosity and surface tension (108), and alter hydrogen availability at the catalyst surface. 

When an alkene reacts with BH3 in THF solution, rapid addition to the double bond occurs three times and a tricilkylborcme, R3B, is formed. For example, 1 molar equivalent of BH3 adds to 3 molar equivalents of cyclohexene to yield tricyclohexylborane. When tricvclohexylborane is then treated with aqueous hydrogen peroxide (H2C>2) in basic solution, an oxidation takes place. The three C-B bonds are broken, -OH groups bond to the three carbons, and 3 equivalents of cyclohexanol are produced. The net effect of the... 

The inhibiting effect of DHQ and its NH3 product was studied on the final step in the network of Fig. 2, the alkene hydrogenation. To avoid confusion with the PCHE olefin formed from DHQ, cyclohexene (CHE) was used as the reactant, and pentylamine (PA) was used as the source of NH3. When the hydrogenation of CHE is performed in the presence of NH3, we have... 

Similarly to peroxycarboxylic acids, DMDO is subject to cis or syn stereoselectivity by hydroxy and other hydrogen-bonding functional groups.93 However a study of several substituted cyclohexenes in CH3CN —H20 suggested a dominance by steric effects. In particular, the hydroxy groups in cyclohex-2-enol and... 

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