Fig. 3. (A) Synthesis of enantiopure fatty acid esters 3 and 4. Reagents and conditions: (a) LiOH, THF/H2O (1 : 1), rt, 90% for 6 and 94% for 7; THF, TSTU, DIPEA, rt, 46% for 3 and 28% for 4. (B) Acylation reaction to obtain virginiafactin B and D standards. (C) HPLC profiles of synthetic and natural virginiafactin B and D. Abbreviations: DIPEA = N,N-diisopropylethylamine; DMF = dimethylformamide; THF = tetrahydrofuran; TSTU = N,N,N′,N′-tetramethyl-O-(N-succinimidyl)uroniumtetrafluoroborate.
