Synthesis of depsipeptide containing analogs.
Reagents and conditions: (a) Et2NH, CH3CN; (b) 32, PyBOP, DIPEA, 79% over 2 steps; (c) 36, PyBOP, DIPEA, 81% over 2 steps; (d) TFA, CH2Cl2; (e) HATU, HOBt, DIPEA, CH3CN, 20% over 2 steps; (f) HATU, HOBt, DIPEA, CH3CN, 23% over 2 steps; (g) TFA, iPr3SiH, CH2Cl2, 82%; (h) TFA, iPr3SiH, CH2Cl2, 89%; (i) N-octanoyl–imidazole, imidazole, DMAP, THF, 50 ° C, 69%; (j) octanoyl chloride, Et3N, 49%.