The crude mixture (30 ml), consisting mainly of 1,4-and 1,5cyclooctadiene, was converted to a mixture of 1,3-and 1,5-cyclooctadiene by treatment for 12 hr at 140°with a solution of sodium (20 g) in tert-amyl alcohol (150 ml).The dienes were recovered from the purified silver nitrate complexes by steam distillation and distillation at atmospheric pressure in purity greater than 99% by glpc on a silicone column. Each sample was identified by ir and nmr spectra: cycloocta-1,3-diene, bp 141.0°, Xmax 227 nm(<""6160); cycloocta-1,4-diene, bp 143.0°; cycloocta-1,5-diene, bp 148.5°.Cycloocta-1,3,5-triene was prepared according to Jones.49 It was freed of bicyclo[4.2.0]octa-2,4-diene by treatment with maleic anhydride according to the procedure of Cope, et al.i0Cycloocta-1,3,6-triene was prepared by the procedure of Sanne and Schlichting.51 The substance was separated from accompanying cycloocta-1,3,5-triene by distillation in a 1-m spinning band column.Any bicyclo[4.2.0]octa-2,4-diene was removed by shaking at 50°with maleic anhydride.cis-and /nms-Hexa-1,3,5-triene were prepared according to Hwa, DeBenneville, and Svens.52 (49) W. O.

No abstract

1,2-dideuterio-cyclohexene, 1,2-dideuterio-cyclooctene, and trans-3,4-dideuterio-hex-3-ene were reacted with three >NO* radicals: 4-hydroxyTempo, di-tert-butyliminoxyl, both used as the actual radicals, and phthalimide-N-oxyl (PINO) generated from N-hydroxyphthalimide (NHPI) by its reaction with tert-alkoxyl radicals (t-RO*) and with lead tetraacetate. In all cases, except the NHPI/Pb(OAc)4 system, only mono >NO-substituted alkenes were produced. The 2H NMR spectra imply that 88-92% of monoadducts were formed by the initial abstraction of an allylic H-atom, followed by capture of the allylic radical by a second >NO*, while the remaining 12-8% appear to be formed by an initial addition of >NO* to the double bond followed by H-atom abstraction by a second >NO*. A substantial and sometimes the major product formed with the NHPI/Pb(OAc)4 system has two PINO moieties added across the double bond. Since such diadducts are not formed with the NHPI/t-RO* system, a heterolytic mechanism is proposed, analogous to that known for the Pb(OAc)4-induced acetoxylation of alkenes. A detailed analysis of the NHPI/Pb(OAc)4/alkene products indicates that monosubstitution occurs by both homolytic and heterolytic processes.

Photooxidation of 1,3-diphenylisobenzofuran (DPBF) in aromatic solvents at 30° gives a monomeric peroxide along with minor amounts of o-benzylphenyl benzoate, whereas in CCl4o-dibenzoylbenzene is the principal reaction product. 1,3-Diphenylisobenzofuran is very susceptible to autoxidation at this temperature (kp/(2kt)1/2 = 4 M−1/2 s−1/2, kp ∼ 105 M−1s−1 2kt ∼ 5 × 108 M−1s−1) yielding a polyperoxide (50%) and o-dibenzoylbenzene (35%). Clearly, in the absence of appropriate control experiments, neither rapid disappearance of DPBF nor production of o-dibenzoylbenzene are sufficient to prove the intermediacy of singlet delta oxygen during molecular oxygen oxidations.

2.1.0]pentane which was recrystallized from ethanol to give 31.0 mg of the pure compound, mp 179-180°. Fractions 142-166 contained 172 mg of starting diene whose nmr spectrum showed no deuterium scrambling within experimental error.The nmr (CCL) of the deuterated vinylcyclopropane consisted of r 8.50 (m, cyclopropyl CH2. rel area 45), 7.64 (m, cyclopropyl CH, rel area 28), 4.84 (d, / = 10 cps, vinyl, rel area 9.4). The nmr (CC14) of the deuterated bicyclo[2.1.0]pentane consisted of 7.82 (d, J = 12 cps, rel area 70), 7.40 id, J = 12 cps, rel area 66), 6.98 (s, rel area 18).A second identical run gave the following results: vinylcyclopropane, nmr (CC14) 8.50 (m, cyclopropyl CH2, rel area 40), 7.64 (m, cyclopropyl CH, rel area 26), 4.84 (d, J = 10 cps, vinyl, rel area 10); bicyclo[2.1.0]pentane, nmr (CC14) 7.82 (d, / = 12 cps, rel area 50), 7.40 (d, J = 12 cps, rel area 45), 6.98 (s, rel area 12).Catalytic Reduction of Deuterio-2,2,5,5-tetraphenylbicyclo[2.1.0]pentane. A sample of deuterio-2,2,5,5-tetraphenylbicyclo[2.1.0]pentane obtained from photolysis of deuterated 1,1,5,5-tetraphenyl-1.4-pentadiene was catalytically reduced with 10% palladium on charcoal as described above. The nmr (CC14) indicated 7.57 (s, C-4 and C-5 CH2, rel area 23) and 6.20 (s, C-2 CH2, rel area 8.5).