Metal-Free Hydroxymethylation of Indole Derivatives with Formic Acid as an Alternative Way to Indirect Utilization of CO2.

Abstract

The selective N-alkylation of indole substrates remains an ongoing research challenge for the relative attenuated nucleophilicity toward nitrogen. Herein, we developed the hydroxymethylation of indole derivatives to afford N-alkylated indole products with formic acid. This metal-free process was promoted by the organic base 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) using phenylsilane as the reductant under mild conditions. Besides, this strategy represents an alternative way for indirect utilization of CO2, considering the facile hydrogenation of CO2 to produce HCOOH.