3.5.2. (*R*)-MTPA Ester of **7** (**7**-4*R*)

White amorphous solid; 1H NMR (CD3OD, 800 MHz) δ<sup>H</sup> 7.575–7.567 (2H, m, MTPA-Ar), 7.459–7.431 (3H, m, MTPA-Ar), 5.804 (1H, t, *J* = 4.9 Hz, H-4), 5.231 (1H, dq, *J* = 8.7, 1.0 Hz, H-12), 4.819 (1H, m, H-11), 3.979 (1H, dd, *J* = 4.5, 1.4 Hz, H-8), 3.633 (3H, s, H-22), 3.579 (3H, s, MTPA-OMe), 2.619 (1H, d, *J* = 18.3 Hz, H-7α), 2.463 (1H, m, H-17), 2.443 (1H, m, H-10α), 2.371 (1H, dd, *J* = 6.2, 5.0 Hz, H-2α), 2.343 (1H, dd, *J* = 8.9, 4.9 Hz, H-2β), 2.300 (1H, m, H-3α), 2.253 (1H, dd, *J* = 18.6, 4.3 Hz, H-7β), 2.149 (1H, m, H-3β), 2.029 (1H, dd, *J* = 13.7, 3.9 Hz, H-10β), 2.003 (2H, m, H-14), 1.654 (3H, d, *J* = 1.0 Hz, H-20), 1.603 (1H, m, H-16α), 1.414 (2H, m, H-15), 1.402 (1H, m, H-16β), 1.295 (3H, s, H-19), 1.109 (3H, d, *J* = 7.0 Hz, H-21); LRESIMS *m*/*z* 609.2 [M + H]+.
