Asymmetric N-alkylations of isatins with enals were shown to be feasible via a prolinol-catalyzed iminium activation, and N-alkylated isatins were obtained in good yields and with excellent enantioselectivity. The biologically useful N-alkylated isatins also served as valuable synthetic precursors, and could be readily converted to chiral N-alkylated indole derivatives. The described method pro...

Cesium fluoride catalyzed direct cyanomethylation of various isatins by using trimethylsilyl acetonitrile (TMSAN) as a nucleophile has been developed. The reaction has been explored for a number of isatins, with various substitutions on its aromatic ring. Further, the versatility of the reaction is demonstrated by converting the direct aldol adducts to the corresponding intermediates of natural...

This paper describes the preparation of a series of 16 anthranilic acids in yields ranging from 51 to 97%, by treating the isatins with NaOH and H2O2. Independently of the nature of the substituent on the aromatic ring, the reactions were complete in 15 min at room temperature, whereas those of isatins containing a substituent on the nitrogen atom required longer reaction time for completion (4...

A highly efficient method for the synthesis of N-alkyl isatins starting from N-alkyl 2-bromo or 2-chloro acetanilides is described. The starting materials are easy to prepare and the yields of isatins are generally high. Operationally the reaction is very simple to run. Even though best results were obtained with a catalytic amount of CuI, the reactions of N-alkyl 2-bromo acetanilides actually ...

We describe an efficient one-step synthesis of pyrrolo[3,4-c]quinolinedione derivatives using ethylenediamine diacetate (EDDA)-catalyzed cascade reactions of isatins and β-ketoamides. It is the first direct conversion of isatins to pyrrolo[3,4-c]quinolinedione derivatives via C-N bond cleavage and isatin ring expansion. Furthermore, this reaction provides a one-step synthetic route for the prod...

A facile synthesis of spirofuran oxindoles via phosphine-mediated reaction of 3-alkyl allenoate with isatins is presented.

The triethylamine promoted three-component reaction of N-(4-nitrobenzyl), N-ethoxycarbonylmethylisoquinolinium bromide, isatins and malononitrile in ethanol afforded spiro[indoline-3,2'-pyrrolo[2,1-a]isoquinolines] in good yields and with high diastereoselectivity. The similar reaction of N-cyanomethylisoquinolinium chloride mainly gave complex indolo[2″,3″:2',3']pyrrolo[3',4':4,5]pyrrolo[2,1-a...

A ytterbium(III)-indapybox catalysed enantioselective decarboxylative addition reaction of β-ketoacids to isatins is described. The biologically important 3-hydroxy oxindoles were obtained in high yields and excellent enantioselectivities.

3-Methyleneoxindole is a cytotoxic metabolite of indole-3-acetic acid with potential for use in cancer therapy. This species and ring-substituted analogues are conveniently synthesised from the corresponding isatins via a Peterson olefination.