(NHC)NiIIH‐Catalyzed Cross‐Hydroalkenylation of Cyclopropene with Alkyne: A Straight Forward Cyclopentadiene Synthesis by NHC‐NiII Assisted C‐C Rearrangement.

Cross‐hydroalkenylation‐rearrangement cascade (HARC) that using cyclopropene 1 and alkyne 2 as substrate pairs was first achieved by using a set of new [NHC‐Ni(allyl)]BArF catalysts. By controlling the NHC‐NiIIH relative insertion reactivity with 1 and 2, a broad scope of cyclopentadiene 3 was obtained highly selectively for the first time. The new NHC‐NiII catalyst structural features were found as the keys for the success. The mild condition employed may serve as an entry for exploring NHC‐NiII assisted vinylcyclopropane rearrangement reactivity.

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