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13.9, 5.3 Hz, 1H), 2.51-2.47 (m, 1H), 2.45 (bs, 1H), 2.25 (bs, 1H), 2.06 (s, 3H), 1.42 (d, J = 7.5
Hz, 3H); 13 C NMR (75 MHz, CDCl3): δ 178.2, 176.2, 175.4, 175.2, 174.3, 156.2, 136.8, 133.4,
131.8, 131.6, 129.1, 128.7, 128.6, 128.3, 127.6, 127.4, 126.7, 126.2, 67.0, 63.7, 53.0, 45.7, 44.3,
43.3, 40.8, 40.4, 39.9, 33.5, 32.7, 24.5, 23.2, 12.7; IR (thin film): ν 2945, 1708, 1499, 1383 cm -1 ;
EI-HRMS calcd for C40H38N3O8 m/z [M+1] + 688.2659; found 688.2637.
H
MeO 2C
Methyl-2-amino-2-benzylhexa-3,4-dienoate (152). To a solution of Boc-protected amine 65f
(0.80 g, 2.4 mmol) in CH2Cl2 (3 mL), was added TFA (3 mL) and the light brown solution was
stirred at rt for 10 min. The volatiles were removed under vacuum (rotary evaporator was used
with a dry ice-cooled trap to collect the TFA) to afford a brown oil which was dissolved in
CH2Cl2 (100 mL) and washed with sat’d aq. NaHCO3 (3 x 50 mL). The organic layer was dried
over MgSO4 and concentrated under vacuum to afford 152 (0.53 g, 95%) as a colorless oil.
1 H NMR (300 MHz, CDCl3): δ 7.32–7.16 (m, 5H), 5.47 (dq, J = 6.3, 3.1 Hz, 1H), 5.35 (dq, J =
6.5, 6.5 Hz, 1H), 3.75 (s, 3H), 3.27 (d, J = 13.2 Hz, 1H), 2.91 (d, J = 13.2 Hz, 1H), 1.70 (dd, J =
7.1, 3.2 Hz); 13 C NMR (75 MHz, CDCl3): δ 202.5, 175.1, 135.8, 129.9, 128.0, 126.8, 96.3, 90.6,
61.0, 52.1, 45.6, 14.0; IR (thin film): ν 3380, 3304, 2950, 1962, 1737, 1197 cm -1 ; MS m/z (%)
231 (7), 216 (25), 199 (19), 178 (27), 172 (35), 140 (100), 91 (76), 80 (57); EI-HRMS calcd for
m/z C14H17NO2 [M] + 231.1259 found 231.1251.
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152
201
H
Bn
NH 2