Dismantling of Vinyl Ethers by Pentanuclear [(iPr P)Ni] H : Facile Cooperative C-O, C-C and C-H Activation Pathways.

The [(iPr P)Ni] H cluster (1) and H C=CHOtBu react at room temperature to form the new pentanuclear NiH carbide [(iPr P)Ni] H (C)(CO) (3), along with an equivalent of isobutylene. This transformation requires the activation of multiple unreactive bonds, including C-H, C-C, and C(sp )-O bond cleavage. Analysis of the reaction mixture by H NMR revealed the production of two additional paramagnetic species, assigned as [(iPr P)Ni] H (C-CH )NiOtBu (4 a) and [(iPr P)Ni] H (C-CH OtBu)NiOtBu (5 a), which arise from C(sp )-O bond cleavage and CH bond rearrangements. The reaction of 1 with H C=CHOSiMe CH Ph produced the isolable 4 a analogue [(iPr P) Ni ]H (CCH )(OSiMe CH Ph) (4 c). An isolable analogue of 5 a was obtained from the reaction of 1 with H C=CHOAd (Ad=1-admantyl), which produced [(iPr P) Ni ]H (CCH OAd)(OAd) (5 d). The utilization of both cluster faces and vertices for bonding substrate fragments in these transformations demonstrates the remarkable flexibility of the robust Ni H core in the cooperative activation of multiple C-O, C-C and C-H bonds.