Transition Metal-Free Aroylation of Diarylmethanes with N-Bn-N-Boc Arylamides and N-Acylpyrroles

In the last 20 years, efficient transition metal catalysts for the alpha-arylation of enolates have been introduced. Despite the popularity and utility of these reactions, there remains room for improvement (reduced costs, elimination of transition metals and specialized ligands). Herein is reported a general, scalable and green method for aroylation of simple diarylmethane pronucleophiles through direct acyl C-N cleavage ofN-Bn-N-Boc arylamides andN-acylpyrroles under transition metal-free conditions. Importantly, a 1 : 1 ratio of the amide to the pronucleophile is employed. Unlike use of Weinreb amides, this method avoids preformed organometallics (organolithium and Grignard reagents) and does not employ cryogenic temperatures, which are difficult and costly to achieve on scale. The operationally simple protocol provides straightforward access to a variety of sterically and electronically diverse 1,2,2-triarylethanones, a group of compounds with high-value in medicinal chemistry.