Abstract

A survey of bases for inducing a Dieckmann cyclization of 2-acylaminobenzoates to give 4- hydroxy-2-quinolinones revealed that hindered non-nucleophilic bases were optimal. However, for sterically demanding substrates sodium hydride performed better. A tandem Michael-Dieckmann reaction for the construction of 4-hydroxy-2-quinolinones is also presented. This methodology is utilized as a key step in the synthesis of the natural product orixalone A.

Keywords: 4-hydroxy-2-quinolinones, tandem Michael-Dieckmann reaction, orixalone A