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BzN
O
O
2-(Benzoylbut-2-ynyl-amino)-2-methylhexa-3,4-dienoic acid but-2-ynyl ester (334). A
solution of amide 333 (0.320 g, 1.08 mmol) in DMF (8 mL) was cooled to 0 °C, and NaH (95%
wt) (0.056 g, 2.23 mmol) was added in one portion. After 2 min, 1-bromo-2-butyne (0.19 mL,
2.23 mmol) was added via a syringe and the reaction mixture was stirred for 30 min at rt. The
reaction mixture was then carefully poured over cold water (100 mL), and the aqueous layer was
extracted with EtOAc (2 x 50 mL). The organic layers were combined and washed with brine,
dried over MgSO4, and concentrated under vacuum to afford 334 (0.415 g, >95% as a mixture of
inseparable diastereomers in 1.5 : 1 ratio).
1 H NMR (300 MHz, CDCl3): δ 7.61-7.59 (m, 2H), 7.42-7.38 (m, 3H), 5.73-5.66 (m, 1H), 5.42-
5.34 (m, 1H), 4.77-4.65 (m, 2H), 4.05-4.01 (m, 2H), 1.85-1.83 (m, 6H), 1.76-1.71 (m, 6H); 13 C
NMR (75 MHz, CDCl3): δ 205.2, 205.2, 171.8, 171.7, 171.3, 136.0, 129.9, 128.3, 128.2, 127.1,
127.0, 92.5, 92.4, 90.2, 90.1, 82.8, 82.7, 80.3, 76.0, 73.4, 64.2, 64.0, 53.6, 53.6, 37.5, 37.4, 20.6,
20.6, 13.8, 13.7, 3.6, 3.5; IR (thin film): ν 2921, 2242, 1967, 1746, 1643 cm -1 ; MS m/z (%) 349
(21), 296 (50), 268 (48), 252 (35), 105 (100); EI-HRMS calcd for C22H23NO3 m/z [M] +
349.1678; found 349.1685.
O
Bz
O
N
1-Benzoyl-5-ethylidene-2-methyl-4-vinyl-1,2,5,6-tetrahydropyridine-2-carboxylic acid but-
2-ynyl ester (176). To a solution of allene-diyne 334 (0.173 g, 0.495 mmol) in toluene (5 mL)
was added [Rh(CO)2Cl]2 (7 mg, 18 µmol) under nitrogen atmosphere. The light yellow solution
176
222
334
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