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EI-HRMS calcd for C30H26NO3 m/z [M-1] + 448.1913; found 448.1929.<br />

BzN<br />

MeO 2C<br />

TBSO<br />

73e<br />

2-(Benzoylbut-2-ynylamino)-2-(tert-butyldimethylsilyloxymethyl)-hexa-3,4-dienoic acid<br />

methyl ester (73e). Prepared by following general procedure F, using: 58i (245 mg, 0.629<br />

mmol), NaH (50 mg <strong>of</strong> a 60% dispersion in mineral oil, 1.3 mmol), 1-bromo-2-butyne (88 µL,<br />

1.1 mmol). Purification by flash chromatography (gradient elution; hexanes-EtOAc, 19 : 1 to 9 :<br />

1, v/v) afforded 73e (237 mg, 85%) as a mixture <strong>of</strong> diastereomers.<br />

1 H NMR (300 MHz, CDCl3): δ 7.71-7.65 (m, 2H), 7.46-7.37 (m, 3H), 5.90-5.86 (m, 1H), 5.41-<br />

5.31 (m, 1H), 4.45 (d, J = 10.1 Hz, 0.66H), 4.44 (d, J = 10.1 Hz, 0.33H), 4.31-4.16 (m, 2H), 3.99<br />

(dq, J = 18.5, 2.3 Hz, 1H), 3.74 (s, 1H), 3.73 (s, 2H), 1.90-1.87 (m, 3H), 1.71 (dd, J = 7.1, 3.2<br />

Hz, 1H), 1.71 (dd, J = 7.1, 3.2 Hz, 2H), 0.87 (s, 9H), 0.06 (s, 3H), 0.05 (s, 3H); 13 C NMR (75<br />

MHz, CDCl3): δ 205.1, 205.0, 172.3, 172.2, 170.6, 136.1, 130.1, 128.1, 127.3, 127.3, 89.9, 89.8,<br />

89.7, 79.8, 79.7, 77.2, 68.3, 68.2, 64.0, 63.9, 52.2, 52.1, 39.4, 39.3, 25.8, 25.7, 18.1, 14.0, 13.7,<br />

3.6, -5.5, -5.6, -5.6, -5.7; IR (thin film): ν 2952, 1968, 1744, 1644 cm -1 ; MS m/z (%) 384 (35),<br />

296 (31), 84 (100); EI-HRMS calcd for C21H26NO4Si m/z [M-57] + 384.1631; found 384.1630.<br />

CbzN<br />

MeO 2C<br />

Me<br />

73f<br />

2-(Benzyloxycarbonylbut-2-ynylamino)-2-methylhexa-3,4-dienoic acid, methyl ester (73f).<br />

Prepared by following general procedure F, using: 65d (400 mg, 1.38 mmol), NaH (110 mg <strong>of</strong><br />

60% dispersion in mineral oil, 2.76 mmol), 1-bromo-2-butyne (157 µL, 1.79 mmol). Flash<br />

chromatography (hexanes-EtOAc, 9 : 1, v/v) afforded 73f (390 mg, 84%).<br />

171<br />

•<br />

•<br />

H<br />

H

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