Oxygenated γ-Butyrolactones

Abstract

In connection with other studies we needed 2-(carboxymethyl)-3-hydroxycyclohexanone lactone 3a. We reasoned that 3a might be obtained from 2-(carboxymethyl)-1,3-cyclohexanedione la via conversion into enol lactone 2a followed by catalytic hydrogenation. Survey of the literature revealed that this approach had already been attempted by Rosenmund et al.² While their reaction sequence was successful in case of the dimedone derivative lb, which was converted into 2b and 3b, the synthesis failed for la because lactonization with acetyl chloride resulted in the formation of a complex mixture of acylated compounds, which could not be characterized with certainty.