A selective 3-acylation of tetramic acids and the first synthesis of ravenic acid.

Abstract

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.

DOI: 10.1002/chem.200902544

Cite this paper

@article{Schlenk2010AS3, title={A selective 3-acylation of tetramic acids and the first synthesis of ravenic acid.}, author={Andrea Schlenk and Randi Diestel and F. D. Sasse and Rainer Schobert}, journal={Chemistry}, year={2010}, volume={16 8}, pages={2599-604} }