Oxidative Addition of a Phosphinite P-O Bond at Nickel

Oxidative addition is an essential elementary reaction in organometallic chemistry and catalysis. While a diverse array of oxidative addition reactions has been reported to date, examples of P-O bond activation are surprisingly rare. Herein, we report the ligand-templated oxidative addition of a phosphinite P-O bond in the diphosphinito aniline compound HN(2-OPPr₂-3,5-Bu-C₆H₂)₂ [H(P₂ONO)] at Ni⁰ to form (PONO)Ni(HPPr₂) after proton rearrangement. Notably, the P-O cleavage occurs selectively over an amine N-H bond activation. Additionally, the ligand cannibalization is reversible, as addition of XPR₂ (X = Cl, Br; R = Pr, Cy) to (PONO)Ni(HPPr₂) readily produces either symmetric or unsymmetric (P₂ONO)NiX species and free HPPr₂. Finally, the mechanisms of both the initial P-O bond cleavage and its subsequent reconstruction are investigated to provide further insight into how to target P-O bond activation.