3.5.3. (*S*)-MTPA Ester of **8** (**8**-2*S*)

White amorphous solid; 1H NMR (CD3OD, 800 MHz) δ<sup>H</sup> 7.680–7.668 (2H, m, MTPA-Ar), 7.428–7.416 (3H, m, MTPA-Ar), 5.581 (1H, dd, *J* = 13.1, 5.3 Hz, H-2), 5.149 (1H, dq, *J* = 8.6, 1.1 Hz, H-12), 4.798 (1H, td, *J* = 9.0, 3.9 Hz, H-11), 3.966 (1H, dd, *J* = 4.6, 1.3 Hz, H-8), 3.615 (3H, s, H-22), 3.551 (3H, s, MTPA-OMe), 2.742 (1H, t, *J* = 14.8 Hz, H-4α), 2.655 (1H, dd, *J* = 17.8, 1.1 Hz, H-7α), 2.526 (1H, dd, *J* = 17.2, 4.1 Hz, H-4β), 2.441 (1H, m, H-17), 2.413 (1H, m, H-10α), 2.316 (1H, m, H-3α), 2.232 (1H, m, H-7β), 2.209 (1H, m, H-3β), 2.023 (1H, dd, *J* = 13.7, 3.9 Hz, H-10β), 1.971 (2H, m, H-14), 1.636 (3H, s, H-20), 1.571 (1H, m, H-16α), 1.381 (2H, m, H-15), 1.372 (1H, m, H-16β), 1.339 (3H, s, H-19), 1.095 (3H, d, *J* = 7.0 Hz, H-21); LRESIMS *m*/*z* 609.2 [M + H]+.
