Reaction Steps
Following the preparation procedure of 22*, the acetylation of 12 afforded 23* with 96% yield. mp 91-93° C.; [α]D=−26.5 (c=0.5, CHCl3); 1H NMR (CDCl3, 400 MHz): δ 7.89 (d, J=8.7 Hz, 2H), 7.37 (d, J=1.9 Hz, 1H), 7.34 (A of ABq, J=8.4, 1.9 Hz, 1H), 7.21 (B of AB, J=8.4 Hz, 1H), 7.10 (d, J=8.7 Hz, 2H), 6.74 (d, J=2.2 Hz, 1H), 6.59 (d, J=2.2 Hz, 1H), 5.64 (bs, 1H), 5.22 (bs, 1H), 3.11 (A of ABq, J=18.0, 4.5 Hz, 1H), 3.04 (B of ABq, J=18.0, 2.4 Hz, 1H), 2.29 (s, 3H), 2.28 (s, 6H), 2.26 (s, 3H), 2.25 (s, 3H); 13C NMR (CDCl3, 400 MHz): δ 168.8, 168.6, 168.3, 167.9, 167.8, 164.9, 154.9, 154.4, 149.7, 142.0, 141.8, 135.7, 131.3, 126.9, 124.2, 123.4, 121.7, 121.5, 109.5, 108.8, 108.0, 67.5, 26.0, 21.0, 20.7, 20.5; HRMS (ESI) calcd for C32H28O13Na (M+Na) 643.1428; found 643.1420.
