Synthesis of substituted indole from 2-aminobenzaldehyde through [1,2]-aryl shift.

A mild, efficient, and simple method for the synthesis of 3-ethoxycarbonylindoles has been developed. Addition of ethyl diazoacetate (EDA) to 2-aminobenzaldehydes cleanly affords the indole core. As opposed to other common approaches for the synthesis of indole, this method displays both excellent functional group tolerance and perfect regiochemical control. This allowed the synthesis of a variety of useful indole building blocks from 2-aminobenzaldehydes derived from readily available anthranilic acids.