A benign and efficient two-pot PMHS reductive amidation of nitroarenes and carboxylic acids

Amide functional groups are found in numerous valuable compounds utilized in the chemical industry and academia. This study reports an efficient two-pot synthesis of amides using nitroarenes and carboxylic acids as starting materials. Polymethylhydrosiloxane (PMHS) was used as an affordable and relatively stable reducing agent to convert nitroarenes into arylamine derivatives in the presence of a Pd(OAc)₂ catalyst. The arylamine derivatives were further directly reacted with tosyl carboxylates generated from carboxylic acids in the second reaction pot. The efficiency of the developed protocol was demonstrated by synthesizing 20 amide products starting from variously substituted nitroarene and carboxylic acid substrates. The reductive amidation reactions were achieved in low to excellent yields at ambient temperatures and within reasonable reaction times.