Silver-Mediated Synthesis of Substituted Benzofuran- and Indole-Pyrroles via Sequential Reaction of ortho-Alkynylaromatics with Methylene Isocyanides.

A silver-mediated reaction between 2-ethynyl-3-(1-hydroxyprop-2-yn-1-yl)phenols or 2-ethynyl-3-(1-hydroxyprop-2-yn-1-yl)anilines and methylene isocyanides has been developed. A sequential 5-endo-dig cyclization and [3 + 2] cycloaddition process is proposed. This synthetic strategy is atom- and step-efficient and applicable to a broad scope of substrates, allowing the synthesis of valuable substituted benzofuran- and indole-pyrroles in moderate to high yields.