Reaction Steps
To a stirred solution of 6A (700 mg, 0.70 mmol) in THF (15 mL) at 0° C. was added a solution of LiOH (25 mg, 1.05 mmol) in H2O (2.4 mL). After stirring for 1 hour, the reaction mixture was diluted with H2O (30 mL), acidified to pH 3-4 with 1M KHSO4, and extracted with EtOAc (3×30 mL). The organic layer was washed with sat NaCl (15 mL), dried (Na2SO4), filtered, and concentrated to give a white solid which was triturated with ether, to give 7A as a white solid (693 mg, 99%) which was used crude directly in the next step. mp=191-193° C.; [α]22D 18.5 (c 0.50, CHCl3); IR νmax 3413, 1711, 1678, 1630, 1451 cm−1; 1H NMR (400 MHz, 5% CD3OD/CDCl3) δ 7.30 (m, 12H), 7.16 (m, 12H), 7.13 (m, 6H), 5.43 (dt, J=15.5 Hz, 6.0 Hz, 1H), 5.30 (dd, J=15.5 Hz, 6.0 Hz, 1H), 4.27 (m, 2H), 4.21 (m, 1H), 3.99 (m, 1H), 3.75 (s, 2H), 3.77 (m, br, 6H), 2.55 (dd, J=12.5 Hz, 6.5 Hz, 1H), 2.44 (dd, J=12.5 Hz, 7.5 Hz, 1H), 2.21 (m, 2H), 2.12 (m, 3H), 2.02 (m, 2H), 1.23 (d, J=7.0 Hz, 3H), 0.83 (d, J=7.0 Hz, 3H), 0.80 (d, J=7.0 Hz, 3H); 13C NMR (100 MHz, 5% CD3OD/CDCl3) δ 173.0, 172.1, 171.6, 171.5, 170.5, 144.9, 144.3, 132.7, 129.8, 129.6, 129.5, 128.2, 127.9, 127.0, 126.7, 69.5, 67.1, 66.7, 58.7, 52.7, 43.5, 40.9, 33.2, 31.5, 31.3, 30.3, 19.2, 19.1, 17.6; LRMS m/z 1013.2 (100%, [M+Na]+).
