Reaction Steps
A solution of 300 mg (1.25 mmol, 1.0 eq) of alkyne 11b in 3.0 mL of dry THF was stirred in a 10 mL round bottom flask at room temperature under argon. To this solution was added 650 μL (3.75 mmol, 5.0 eq) of N,N-diisopropylethylamine followed by 340 mg (1.50 mmol, 1.2 eq) of 3-Iodo-acrylic acid ethyl ester. This solution was then sparged with argon for 10 minutes, at which point 44 mg (0.063 mmol, 0.05 eq) of PdCl2(PPh3)2 and 12 mg (0.063 mmol, 0.05 eq) of CuI were added at once and the solution was stirred at room temperature until the reaction was complete by TLC (3:1 hexane:acetone, Rf=0.30). Upon completion (˜4 hours) the reaction was diluted with EtOAc and washed with 1.0 M HCl. The aqueous layer was then extracted twice with EtOAc. The combined organic fractions were then washed with saturated NaHCO3 and brine and then dried over MgSO4. Purification via silica gel flash chromatography (hexane/EtOAc) yielded 252 mg (63%) of 11c as a pale brown oil, Rf 0.47 (1:1 hexane:EtOAc). 1H-NMR (500 MHz, CDCl3): 7.92 (1H, s), 7.87 (1H, d, J=7.9 Hz), 7.56 (1H, dt, J=7.8 Hz, 1.2 Hz), 7.41 (1H, d, J=7.6 Hz), 7.35 (1H, t, J=7.6 Hz), 6.11 (1H, dd, J=11.5 Hz, 2.4 Hz), 6.04 (1H, d, J=11.5 Hz), 4.35 (1H, dq, J=7.1 Hz, 2.2 Hz), 4.21 (2H, q, J=7.1 Hz), 2.39 (3H, s), 1.57 (3H, d, J=7.1 Hz), 1.27 (3H, t, J=7.1 Hz). 13C-NMR (500 MHz, CDCl3): 185.43, 164.92, 152.18, 147.04, 145.37, 142.09, 136.11, 131.86, 129.00, 128.44, 128.35, 126.69, 123.28, 105.40, 79.35, 60.52, 29.88, 24.64, 14.42, 14.18. IR (cm−1): 2976 (m), 2213 (w), 1719 (s), 1653 (s), 1603 (m), 1579 (s), 1384 (m), 1355 (m), 1291 (m), 1183 (vs), 905 (s). HRMS (EI) calcd. for C20H19NO4: 337.1314. found: 337.1322.
