The nmr spectra Of XII-eqOAc in CCh and CC,DC, are essentially the same except for the signal positions (Figures 4a and 4f). Decoupling experiments similar to the above revealed signal assignments and all J's . These results are consistent with the structure of XII-eqOAc. Long-range J's in these compounds are listed in Table 11.Procedure for the Nmr Spectral Assignments of Benzo[3,4]tricyclo-[3.2.1.O2J]octene Deriatives XI. The spectrum of XI-exo-OAc in CCI4 ( Figure 5a) shows complicated signals due to two protons at about r 7.8 and a broad doublet due to two protons at about T 8.28, so that the signal assignment was difficult. Moreover, the nmdr spectrum irradiated at 7 7.00 (a broad doublet signal) also gave no insight, as shown in Figure 5b. However, the appearance of only one signal at r 7.00 assignable to the bridgehead proton can exclude the XV structure. Further, a singlet at T 5.55 indicates a Cs em-acetoxylzl in the benzo[3,4]tricyclo[3.2.1.0~~~]oct-3-ene system. The spectrum in C6D6 (Figure 5c) shows all proton signals separated. Double irradiation on a thin triplet at 7 5.35 assignable to Hen (Figure 5d) made each peak of a doublet at 7 7.02 due to the bridgehead Ha and a multiplet around T 8.5 fairly sharp, and caused a quartet of triplets at T 8.38 (J = 7.0, 5.0, and 1.0 Hz) to collapse into a quartet of doublets ( J = 7.0, 5.0, and 1.0 Hz). On double irradiation at 7 5.55 (HJ (Figure 5e), a doublet of quartets at r 7.85 ( J = 11.6, 4.9, and 2.8 Hz), the quartet of triplets at T 8.38, the multiplet at about T 8.5, a doublet at T 9.06 having some broadening (J = 11.6 Hz), and the thin triplet at T 5.35 due to Hsn were changed into a doublet of doublets ( J = 11.6 and 2.8 Hz), a quartet of doublets ( J = 7.0, 5.0, and 1.0 Hz), a sharper signal, a doublet of doublets ( J = 11.6 and 0.6 Hz), and a thin doublet ( J = 1.0 Hz), respectively. Triple irradiation on H g and Hgn (Figure 5f) gave important changes in the two signals at T 8.38
