Reaction Steps
NiCl2.6H2O (0.26 g, 1.09 mmol) then portionwise NaBH4 (0.17 g, 4.49 mmol) were added to a stirred solution of unsaturated ketone 39 (2.60 g, 2.19 μmol) in 80 mL of 3:2 MeOH/THF at 0° C. After 1 h, the reaction mixture was evaporated and filtered through Celite using Et2O (30 mL) as an eluent. The organic phase was concentrated and the residue was purified by flash chromatography (EtOAc/hexane 1:9) to yield 1.98 g of 40 (76%) as a colorless oil: IR (CHCl3) 2955, 2927, 2855, 1711, 1614, 1518, 1461, 1251, 1076, 835, 773 cm−1; 1H NMR (300 MHz, CDCl3) δ 7.46 (m, 6H), 7.27 (m, 1H), 6.85 (m, 2H), 5.60 (m, 2H), 5.43 (s, 1H), 5.40 (m, 1H), 5.27 (m, 1H), 4.52 (m, 1H), 4.11 (dd, J=11.1, 4.7 Hz, 1H), 3.91 (m, 2H), 3.78 (s, 3H), 3.55 (m 2H), 3.50 (m, 1H), 3.35 (m, 1H), 2.67 (m, 1H), 2.58 (m, 1H), 2.51 (m, 1H), 2.41 (m, 1H), 2.01 (m, 1H), 1.68 (m, 3H), 1.41 (m, 5H), 1.23 (d, J=7.1 Hz, 3H), 0.96 (d, J=6.7 Hz, 3H), 0.90 (s, 9H), 0.89 (s, 9H), 0.88 (m, 1H), 0.87 (m, 3H), 0.80 (s, 9H), 0.78 (m, 6H), 0.10 (s, 3H), 0.08 (s, 3H), 0.04 (s, 3H), 0.03 (s, 6H), 0.01 (s, 3H); 13C NMR (75 MHz, CDCl3) δ 211.9, 159.8, 144.5, 144.3, 134.4, 132.9, 132.4, 130.9, 128.6, 127.9, 127.8, 127.7, 127.1, 126.8, 113.4, 100.8, 86.7, 83.1, 79.9, 72.8, 72.2, 66.4, 65.1, 55.1, 48.3, 42.3, 41.5, 41.2, 38.1, 35.7, 35.0, 31.2, 29.8, 29.7, 26.2, 25.92, 25.87, 20.2, 19.4, 18.4, 18.1, 18.0, 15.2, 13.2, 12.1, 9.6, −3.0, −3.5, −3.7, −4.2, −4.28, −4.34; LRMS (ESI) 1211.9 (30 mL), 1031.8, 870.4, 684.3, 366.4, 243.1; HRMS (ESI) calcd for C72H112O8Si3Na 1211.7563 (30 mL), found 1211.7616; [α]20D +1.6 (c 0.50, CHCl3).
