Palladium-Catalyzed <i>N</i>-Allylic Alkylation of Pyrazoles and Unactivated Vinylcyclopropanes

An efficient palladium-catalyzed <i>N</i>-allylic alkylation of pyrazoles and unactivated vinylcyclopropanes is demonstrated, affording various <i>N</i>-alkyl pyrazoles in ≤99% yield. This protocol displays high atom economy, a broad range of substrates, and excellent regioselectivity and stereoselectivity. Late-stage modification of bioactive molecules, scaled-up reaction, and divergent derivatization documented the practicability of this methodology. The preliminary mechanistic investigation hinted that the Pd-H species promotes the ring opening of cyclopropanes.