Scheme 2. Semi-synthesis of C16-aminoratjadones from (+)-ratjadone A. Reagents and conditions: (a) IBX (1.1 equiv.), (DMSO, 0.075 M), 23 °C. Addition of 16 h + 23 °C. 24 h, 75% brms 13, 8% brms 14, 15% brms 15. (b) (NH4)OAc (10 equiv.), NaCNBH3 (2.0 equiv.), (MeOH), 23 °C, 13 h + 40 °C, 2 h, 34% brsm 16, 21% brms 17, 8% brsm 18, 2% brsm 19.
