Reaction Steps
To a stirred solution of unsaturated ester 65 (2.02 g, 2.10 μmol) in MeOH (10 ml), THF (1 ml) at 0° C. was added 0.25 g of NiCl·6H2O then portionwise NaBH4 (0.16 g). After 1 h, the reaction mixture was evaporated and filtered with Celite using Et2O as an eluent (5 ml). The organic phase was concentrated and the residue was purified by flash chromatography (EtOAc/Hexane 1:9) to yield 1.96 g (2.04 μmol) of product 66 (97%) as a colorless oil: IR (CHCl3) 2956, 2929, 2856, 1735, 1613, 1514, 1479, 1448, 1374, 1249, 1174, 1072, 836, 773, 706 cm−1; 1H NMR (300 MHz, CDCl3) δ 7.53 (m, 6H), 7.33 (m, 11H), 6.84 (m, 2H), 5.81 (dd, J=15.7, 6.1 Hz, 1H), 5.65 (m, 1H), 5.45 (m, 2H), 4.65 (m, 1H), 4.56 (d, J=10.9 Hz, 1H), 4.45 (d, J=10.9 Hz, 1H), 4.14 (q, J=7.1 Hz, 2H), 3.96 (m, 1H), 3.80 (s, 3H), 3.62 (m, 2H), 3.14 (m, 1H), 2.79 (m, 1H), 2.43 (m, 1H), 2.23 (m, 1H), 1.72 (m, 2H), 1.54 (m, 3H), 1.28 (t, J=7.1 Hz, 3H), 1.06 (d, J=6.7 Hz, 3H), 1.01 (d, J=6.9 Hz, 3H), 0.97 (s, 18H), 0.93 (d, J=6.4 Hz, 3H), 0.17 (s, 3H), 0.154 (s, 3H), 0.151 (s, 3H), 0.14 (s, 3H); 13C NMR (75 MHz, CDCl3) δ 173.6, 158.8, 144.4, 134.6, 133.6, 132.1, 131.2, 129.1, 128.7, 127.7, 126.8, 126.4, 103.4, 86.6, 86.1, 73.8, 72.8, 66.5, 65.2, 60.0, 55.1, 42.8, 42.3, 35.4, 35.1, 32.3, 29.4, 26.0, 25.9, 18.4, 18.1, 14.6, 14.2, 13.9, −2.9, −4.0, 4.1; HRMS (ESI) calcd for C59H86O7Si2K 1001.5549 (M+K)+, found 1001.5586; [α]20D−9.8 (c 0.95, CHCl3).
