Dismantling of Vinyl Ethers by Pentanuclear [( i Pr 3 P)Ni] 5 H 6 : Facile Cooperative C−O, C−C and C−H Activation Pathways

The [( i Pr 3 P)Ni] 5 H 6 cluster ( 1 ) and H 2 C=CHO t Bu react at room temperature to form the new pentanuclear NiH carbide [( i Pr 3 P)Ni] 5 H 4 (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 3 )−O bond cleavage. Analysis of the reaction mixture by 1 H NMR revealed the production of two additional paramagnetic species, assigned as [( i Pr 3 P)Ni] 4 H 4 (C‐CH 3 )NiO t Bu ( 4 a ) and [( i Pr 3 P)Ni] 4 H 4 (C‐CH 2 O t Bu)NiO t Bu ( 5 a ), which arise from C(sp 2 )−O bond cleavage and CH bond rearrangements. The reaction of 1 with H 2 C=CHOSiMe 2 CH 2 Ph produced the isolable  4 a analogue [( i Pr 3 P) 4 Ni 5 ]H 4 (CCH 3 )(OSiMe 2 CH 2 Ph) ( 4 c ). An isolable analogue of 5 a was obtained from the reaction of 1 with H 2 C=CHOAd (Ad=1‐admantyl), which produced [( i Pr 3 P) 4 Ni 5 ]H 4 (CCH 2 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 5 H 4 core in the cooperative activation of multiple C−O, C−C and C−H bonds.