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To a solution of diene 156a (20 mg, 36 µmol) in THF (2.5 mL) was added Pd/C (5 mg, 10% by
wt.), and the reaction vessel was sealed with a rubber septum and H2 atmosphere was introduced
from a balloon via a needle. The heterogeneous reaction mixture was stirred for 4 h at rt. The
mixture was then filtered over a plug of celite eluting with CH2Cl2 and the collected solution was
concentrated under vacuum. The crude residue was purified by flash chromatography (EtOAc :
hexanes, 1 : 1 to 1 : 0, v/v) to afford 161a (16 mg, 80%).
1 H NMR (300 MHz, CDCl3): δ 7.43-7.30 (m, 6H), 7.08-7.03 (m, 4H), 4.37 (d, J = 18.2 Hz, 1H),
4.38-4.34 (m, 1H), 4.21 (d, J = 18.2 Hz, 1H), 3.78 (s, 3H), 3.43-3.33 (m, 3H), 3.22 (d, J = 13.2
Hz, 1H), 2.68-2.65 (m, 2H), 2.50 (dq, J = 12.9, 2.6 Hz, 1H), 2.34 (sept, J = 7.2 Hz, 2H), 2.27-
2.15 (m, 1H), 0.98 (t, J = 7.4 Hz, 3H); 13 C NMR (75 MHz, CDCl3): δ 177.1, 175.9, 170.2, 158.4,
153.8, 146.0, 133.6, 132.3, 131.0, 130.0, 129.2, 128.9, 128.8, 128.4, 125.9, 64.7, 52.2, 48.9, 47.9,
40.8, 40.6, 40.1, 26.1, 20.0, 19.3, 12.7; IR (thin film): ν 2953, 1837, 1743, 1709 cm -1 ; MS m/z
(%) 555 (10), 464 (80), 420 (65), 321 (100); HRMS calcd. for C31H29N3O7 [M] + m/z 555.2005,
found 555.1992.
O
O
O
N
H
N
Bn
O
N
10c-Benzyl-5-ethyl-1-isobutylimino-9-methyl-6,7,7a,10a,10b,10c-hexahydro-1H-2-oxa-3a,9-
diazadicyclopenta[a,h]naphthalene-3,4,8,10-tetraone (161b). To a solution of diene 156b (56
mg, 0.12 mmol) in THF (7 mL) was added Pd/C (10 mg, 10% by wt.), and the reaction vessel
was sealed with a rubber septum and H2 atmosphere was introduced from a balloon via a needle.
The heterogeneous reaction mixture was stirred for 4 h at rt. The mixture was then filtered over a
plug of celite eluting with CH2Cl2 and the collected solution was concentrated under vacuum.
161b
216
O