2-Methyl-2-butene → 6-chloro-1H-indole-2,3-dicarboxylic acid 2-ethyl ester

Participants

Reaction Steps

To a solution of commercially available 6-chloro-3-formyl-1H-indole-2-carboxylic acid ethyl ester in t-BuOH and 2-methyl-2-butene (50 eq) was added 9.2 eq NaClO2 (9 eq) and aq. NaH2PO4 (7 eq) and stirred 12 h at room temperature. After concentration the mixture was dissolved in H2O and adjusted to pH7 and then extracted with EtOAc; partial concentration of the organic phase precipitated the product in 52% yield.

Provenance & Evidence