Reaction Steps
The procedure for 32 was used with 15 (1.31 g, 2.28 μmol), 64 (1.20 g, 3.01 mmol) and n-BuLi (1.88 mL, 1.20 mmol) to yield the ynone (1.79 g, 86%) after flash column chromatography (EtOAc/hexane 1:19) as a colorless oil: IR (CHCl3) 2929, 2856, 2209, 1675, 1471, 1462, 1385, 1254, 1093, 836, 775, 705 cm−1; 1H NMR (300 MHz, CDCl3) ε7.56-7.53 (m, 6H), 7.38-7.25 (m, 9H), 5.79 (dd, J=15.6, 7.2 Hz, 1H), 5.67 (dt, J=15.6, 4.9 Hz, 1H), 4.36 (m, 1H), 3.69-3.66 (m, 4H), 3.63 (t, J=4.1 Hz, 1H), 2.86 (m, 1H), 2.72 (m, 1H), 2.45 (m, 1H), 1.76 (m, 1H), 1.67-1.51 (m, 3H), 1.34 (m, 1H), 1.29 (d, J=7.1 Hz, 3H), 1.14 (d, J=6.8 Hz, 3H), 1.00-0.97 (m, 28H), 0.18-0.13 (m, 18H); 13C NMR (75 MHz, CDCl3) δ 186.0, 144.2, 132.8, 128.6, 127.9, 127.7, 126.8, 96.7, 86.8, 83.1, 77.8, 71.6, 64.8, 63.2, 50.1, 42.3, 37.2, 31.7, 30.9, 30.2, 26.0, 25.9, 25.8, 18.3, 18.2, 18.0, 17.3, 15.4, 14.8, −3.9, −4.1, −4.6, −4.7, −5.3; LRMS (ESI) 933.6 [M+Na]+, 795.5, 665.2, 496.1, 413.2, 243. 1; HRMS (ESI) calcd for C55H86O5Si3Na 933.5681 [M+Na]+, found 933.5692; [α]20D−9.5 (c 0.55, CHCl3).
