3.6.4. (*R*)-PGME Amide of **8** (**8**-18*R*)

Major isomer; brown amorphous solid; 1H NMR (CD3OD, 800 MHz) δ<sup>H</sup> 7.367–7.324 (5H, m, PGME-Ar), 5.473 (1H, s, PGME-H-1), 5.111 (1H, br d, *J* = 8.7 Hz, H-12), 4.759 (1H, td, *J* = 9.0, 4.0 Hz, H-11), 4.060 (1H, dd, *J* = 12.4, 5.2 Hz, H-2), 3.933 (1H, dd, *J* = 4.8, 1.0 Hz, H-8), 3.695 (3H, s, PGME-OMe), 2.667 (1H, d, *J* = 18.0 Hz H-7α), 2.566 (1H, m, H-4α), 2.462 (1H, m, H-17), 2.445 (1H, m, H-4β), 2.370 (1H, m, H-10α), 2.232 (1H, m, H-3α), 2.206 (1H, m, H-7β), 1.975 (1H, m, H-10β), 1.919 (2H, m, H-14), 1.815 (1H, m, H-3β), 1.574 (3H, d, *J* = 0.5 Hz, H-20), 1.546 (1H, m, H-16α), 1.328 (1H, m, H-16β), 1.304 (2H, m, H-15), 1.300 (3H, s, H-19), 1.108 (3H, d, *J* = 6.8 Hz, H-21); LRESIMS *m*/*z* 526.3 [M + H]+.
