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The reaction of cyclopentadiene with 1,1,3,3-tetrakis(methoxycarbonyl)propene gives an endo and exo mixture of dimethyl 2-{3,3-bis(methoxycarbonyl)bicyclo-[2.2.1]hept-5-en-2-yl}malonate, which by base-mediated retro-Michael reaction gives stereoselectively the cis-isomer of dimethyl 2-{4-[2,2-bis(methoxycarbonyl)vinyl]cyclopent-2-en-1-yl}malonate.

Reaction of ozone with three kinds of olefins in air was studied. H2O2, CH3OOH, and HOCH2OOH were collected and analyzed with HPLC with a fluorometric detector. Direct reaction of CH2OO with H2O was found to be the source of HOCH2OOH. CH3OOH was formed only from the olefins which have a methyl group. Detailed reaction mechanisms are discussed.

The irradiation of hypoiodites generated from cyclobutanols prepared by means of N-methylation and hydrolysis of 2+2 photocycloadducts between 4-acetoxy-2-quinolone and cyclopentene or 2,3-dimethylbut-2-ene induced rearrangements of the corresponding alkoxy radicals to give 2,3-furanoquinol-4-ones or a ring expanded product.

Heteropoly acid (HPA) was used as an oxidant in the Wacker catalyst system. Among the catalyst systems examined, the PdSO4–H3PMo6W6O40 catalyst system showed the highest activity with regard to the oxidation of cycloolefins, particularly cyclopentene and cyclohexene, to the corresponding cyclic ketones. The largest total turnover number with respect to Pd2+ was found to be 85 in water containing 20% N-methylformamide by volume. The initial rate of cyclohexene oxidation was expressed asVo=k[Cyclohexene]1.0[PdSO4]1.0[HPA]0[O2]0.The rate-determining step was suggested as being where cyclohexene was oxidized to cyclohexanone by Pd(II) salt. The apparent activation energy was 7.8 kcal mol−1 (1 cal=4.18 J). In the catalytic oxidation of cycloolefins (CnH2n−2: n=5, 6, 7, and 8), the yield of alicyclic ketone decreased as the carbon number n increased. Methyl-substituted cyclohexenes exhibited lower reactivities than cyclohexene.

Dichlorobis(N,N-dialkylacetamide)palladium(II) complex catalyzes the oxidation of cyclopentene to cyclopentanone by molecular oxygen in alcoholic solvent, in which one atom of molecular oxygen in incorporated.

Direct photolyses at 185 nm of bicyclo[3.2.0]hept-6-ene and bicyclo[4.2.0]oct-7-ene in pentane afforded acetylene and the fragment cycloalkenes as the major photoproducts, whereas the Woodward-Hoffmann allowed ring-opening giving rise to 1,3-diene was a minor process.

Whereas 2-methyl-2,3-epoxy-6-triethylgermyl-6-tridecene gave the expected alkylidenecyclopentanol upon treatment with TiCl4, 5-triethylgermyl-5-dodecenal dimethyl acetal provided the unexpected cyclohexene derivative. Transformation of 1-triethylgermylcycloalkenes into 1-iodocycloalkenes is also described.

Trimethylsilyl trifluoromethanesulfonate promotes ring opening reactions of oxirane derivatives. The reaction course is highly affected by the structures and substitution pattern of the substrates. Tetra-, tri-, and 2,2-disubstituted oxiranes and simple cycloalkene oxides are converted to the corresponding allylic alcohol trimethylsilyl ethers. The overall transformation is interpreted in terms of trans addition of the silyl trifluoromethanesulfonate to the oxirane ring followed by base-promoted anti elimination of a trifluoromethanesulfonic acid element. 2,3-Dialkyl- or monoalkyloxiranes isomerize to the corresponding ketones and aldehydes, respectively. (Z)-Cyclooctene oxide undergoes the transannular reaction to give endo-cis-2-trimethylsiloxybicyclo[3.3.0]octane. The reaction of 6-methyl-5-hepten-2-one oxide produces 2,2,6-trimethyl-3-trimethylsiloxy-3,4-dihydro-2H-pyran. 1,2-Methyl migration takes place in the reaction of (E)-3α-t-butyldimethylsiloxy-5α-pregnene 17α,20-oxide to afford 3α-t-butyldimet...

The epoxidation of alkenes with H2O2 was carried out in the presence of molybdenum oxide(VI)–(Bu3Sn)2O in CHCl3 at 25 °C. In the oxidation of cyclohexene, styrene, and α-pinene, the addition of amines was indispensable and the yields of oxides reached 87 to 57%.

Oxidation of cyclopentene by RuCl3–NaOCl catalyst in an aqueous-organic two phase system was investigated by changing compositions of solvent system and additives to the aqueous solution. Use of acetonitrile as a cosolvent enhanced the reaction rate greatly, and addition of NaOH improved the yield of glutaric acid up to 80%.