Efficient synthesis of N-methoxyindoles via alkylative cycloaddition of nitrosoarenes with alkynes.

[reaction: see text] N-Methoxyindoles are produced in moderate to excellent yields from the reaction between nitrosoarenes and alkynes in the presence of K2CO3/(CH3)2SO4. Terminal alkynes with conjugating substituents afford 3-substituted N-methoxyindoles exclusively. The analogous reactions with methyl propiolate provide a one-step preparation of phytoalexin analogues from Wasabi.