Asymmetric cross-aldol reaction of isatin and ketones catalyzed by crude earthworm extract as efficient biocatalyst

Abstract

The asymmetric cross-aldol reaction of simple ketones (acetone, cyclohexanone) with isatin derivatives in the presence of crude extract from earthworms as green and effective biocatalyst proceeds easily in MeCN/H2O (1:1) as solvent to afford 3-hydroxy-2-oxindoles derivatives. Ten compounds were synthesized in high yields (62–88%) and moderate ee (29–42%). Structure of the synthesized compounds has been characterized on the basis of NMR spectra and CHN analysis. The ee of the obtained compounds was determined by chiral phase HPLC analysis.

Keywords

• asymmetric cross-aldol reaction
• 3-hydroxy-2-oxindoles derivatives
• earthworm extract biocatalyst
• isatin
• acetone
• cyclohexanone
• acetophenone