Selective Mono- and Diamination of Ketones in a Combined Copper-Organocatalyst System

Herein, we report a simple and mild protocol for the chemoselective mono- and diamination of ketone using pyrazole as the amine source in a combined copper-organocatalyst system. Various substrates are compatible, providing the corresponding products in moderate to good yields. This strategy gives an efficient and convenient solution for the synthesis of alpha-pyrazole and alpha,alpha-dipyrazole ketone derivatives. The control experiment demonstrates that in situ generated hydrazone is a key intermediate in the transformation.

Automated summary

This study presents a simple and mild method for the chemoselective mono- and diamination of ketones using pyrazole as the amine source in a combined copper-organocatalyst system. The strategy offers an efficient and convenient solution for synthesizing alpha-pyrazole and alpha,alpha-dipyrazole ketone derivatives, with moderate to good yields. The control experiment confirms the key intermediate of in situ generated hydrazone in the transformation.