Synthesis of Indoles via 3 2 Cycloaddition Reactions

An interesting 4 + 1 approach based on the utilization of a-diazophosphonate as a one-carbon synthon toward the construction of a functionalized indole framework was illustrated by Nakamura. This was achieved by combining the Rh(II)-catalyzed N—H insertion reaction with the base-mediated intramolecular Horner- 

In addition, this reaction seems to be limited to the corresponding dibromides as coupling components, since attempts to employ the chloro analogs provided either diminished yields of the products 260 or a complete lack of reactivity. 

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