Fig. 7: Mechanistic studies and reaction models.
From: NHC-Ni(II)-catalyzed cyclopropene-isocyanide [5 + 1] benzannulation

a Effect of NHC and the three-substituent on indene derivative formation; b [trans-IPr-NiBr2(CNDIPP)] crystal structure, IR studies, and NaBArF effect; c NHC effect on 2b oligomerization; d A cyclopropyl carbonitrile alkylation directed rearrangement; e Syn-addition of a cationic (NHC)Ni(II) species to cyclopropene.