Metal-free synthesis of 3,3′-bisindolylmethanes in water using Ph3C+[B(C6F5)4]− as the pre-catalyst

Abstract

Here, we report a highly efficient catalytic species generated from Ph₃C⁺[B(C₆F₅)₄]⁻ by the water mediated Friedel–Crafts type reaction of indoles with carbonyl compounds to afford 3,3′-bisindolylmethanes (BIMs). This scalable method is applicable to a wide variety of carbonyl compounds, including unprotected sugar molecules and carbonyl compounds derived from drugs and natural products.