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O
Ph N
Bn
MeO2C 1-Benzoyl-2-benzyl-5-ethylidene-6-oxo-4-vinyl-1,2,5,6-tetrahydropyridine-2-carboxylic acid
methyl ester (146e). To a solution of 145e (28 mg, 70 µmol), in toluene (2 mL), was added
[Rh(CO)2Cl]2 (2.7 mg, 6.9 µmol) at rt under Ar atmosphere. The reaction was stirred for 1 h at rt
and the yellow solution was then applied to a small silica gel column and eluted
(EtOAc/hexanes, 1 : 9, v/v) to give 146e (21 mg, 75%) after removal of the solvents.
1 H NMR (300 MHz, CDCl3): δ 7.58-7.55 (m, 2H), 7.49-7.44 (m, 1H), 7.39–7.34 (m, 2H), 6.27
(dd, J = 17.3, 10.8 Hz, 1H), 6.01 (q, J = 7.5 Hz, 1H), 5.80 (s, 1H), 5.56 (dd, J = 17.3, 1.4 Hz,
1H), 5.31 (dd, J = 10.8, 1.4 Hz, 1H), 4.03 (d, J = 13.8 Hz, 1H), 3.75 (s, 3H), 3.41 (d, J = 13.8 Hz,
1H), 1.78 (d, J = 7.5 Hz, 3H); 13 C NMR (75 MHz, CDCl3): δ 176.1, 171.3, 165.6, 141.1, 138.6,
136.4, 134.5, 133.1, 131.5, 131.5, 128.3, 128.1, 127.8, 127.1, 125.9, 120.0, 118.6, 69.9, 53.3,
42.0, 16.3; IR (thin film): ν 3027, 2945, 1746, 1686, 1271, 1219 cm -1 ; EI-HRMS calcd for
C25H23NO4 m/z [M] + 401.1627; found 401.1639.
O
146e
General procedure I for preparation of diamides 154a and 154b.
MeO 2C
O
HN
H
N
Bn
O
154a
[(2-Benzyl-5-ethylidene-6-oxo-4-vinyl-1,2,5,6-tetrahydropyridine-2-carbonyl)amino]acetic
acid methyl ester (154a). To a solution of ester 146a (0.916 g, 3.08 mmol) in THF (60 mL) was
added water (60 mL) at rt, followed by LiOH·H2O (0.264 g, 6.15 mmol). The homogeneous
solution was stirred for 5 min, and then acidified with sat’d aq. NH4Cl (200 mL) and 1M HCl (20
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