A Selective 3-Acylation of Tetramic Acids and the First Synthesis of Ravenic Acid

作者:Schlenk Andrea; Diestel Randi; Sasse Florenz; Schobert Rainer*
来源:Chemistry - A European Journal, 2010, 16(8): 2599-2604.
DOI:10.1002/chem.200902544

摘要

3-Acyltetramic acids, including delicate 3-oligoenoyl derivatives, such as the Penicillium metabolite ravenic acid, were prepared in two high-yielding steps. Reaction of tetramic acids with the ylide Ph(3)PCCO afforded exclusively the corresponding 3-acylylidenetetramic acids. These were amenable to Wittig olefinations with aliphatic, aromatic, saturated and unsaturated aldehydes after deprotonation with KOtBu. Due to its simplicity, selectivity and tolerance of pH-sensitive groups this method is superior to the established acylation protocols by Jones and Yoshii. It is also applicable to the synthesis of 3-acyltetronic acids. The new 3-oligoenoyl tetramic acids exhibited structure-dependent antimicrobial and cytotoxic activity.

  • 出版日期2010