First asymmetric reduction of isatin by marine-derived fungi

Abstract

In this study, whole cells of marine-derived fungi were used to reduce isatin (1H-indole-2,3-dione) to dioxindole (3-hydroxyindolin-2-one) for 7 days at 32°C. The screening showed that several strains could reduce isatin and produce the enantioenriched dioxindole. The best conversions were obtained by Cladosporium sp. CBMAI 1237 and Westerdykella sp. CBMAI 1679, however, the best enantiomeric excess was obtained only by Aspergillus sydowii CBMAI 935 (66% ee). In conclusion, marine-derived fungi show potential for asymmetric and chemoselective reduction of isatin (1H-indole-2,3-dione).