Reaction Steps
(Z)-(4-chloro-3-buten-1-ynyl)trimethylsilane (1.41 mL, 8.16 mmol) and n-butylamine (0.81 mL, 8.16 mmol) were added to a solution of Pd(Ph3)4 (628 mg, 0.54 mmol) in benzene (25 mL). The solution was stirred at 25° C. for 15 minutes and then added to a mixture of Compound 61 (2.204 g, 5.44 mmol) and CuI (207 mg, 1.09 mmol) in benzene (25 mL) at zero degrees C. The solution was stirred two hours at zero degrees C, poured into brine (100 mL) and extracted with dichloromethane (3×100 mL). The organic extracts were dried (Na2SO4), concentrated and purified by flash chromatography (10 percent Et2O in petroleum ether) to give Compound 62 (2.606 g, 91 percent) as a colorless oil; Rf =0.46 (30% Et20 in petroleum ether); [a]D25 =+17.4° (c .2.7 , CH2Cl2); IR (thin film) νmax 1720 cm-1 ; 1H NMR (500 MHz, CDCl3) δ 9.50 (s, 1 H, C=CH--O), 6.65 (s, 1 H, C=CH--CO2), 5.86 (ABq, J =11.0 Hz, Dn =30 Hz, 2 H, CH=CH), 4.38-4.29 (m, 2 H, ethylene ketal), 4.15-4.09 (m, 2 H, ethylene ketal), 3.74 (s, 3 H, CO2Me), 2.67 (ABq, J =14.1 Hz, Dn =61 Hz, 2 H, CH2), 0.89 (t, J =7.3 Hz, 9 H, Si(CH2CH3)3), 0.66 (m, 6 H, Si(CH2CH3)3), 0.17 (s, 9 H, SiMe3); 13C NMR (125 MHz, CDCl3) δ 166.6, 161.2, 161.0, 143.7, 121.2, 118.6, 114.9, 112.0, 103.5, 101.3, 100.7, 95.5, 85.7, 72.1, 65.0, 64.6, 51.5, 50.0, 6.8, 5.9, -0.4; FAB HRMS (NBA/CsI) m/e 660.1213, M+Cs+ calcd for C27H37NO6Si2 660.1214.
