This review classifies and summarizes the past 10-15 years of advancements in the field of metal-involving (i.e., metal-mediated and metal-catalyzed) reactions of oximes. These reactions are diverse in nature and have been employed for syntheses of oxime-based metal complexes and cage-compounds, oxime functionalizations, and the preparation of new classes of organic species, in particular, a wide variety of heterocyclic systems spanning small 3-membered ring systems to macroheterocycles. This consideration gives a general outlook of reaction routes, mechanisms, and driving forces and underlines the potential of metal-involving conversions of oxime species for application in various fields of chemistry and draws attention to the emerging putative targets.

Three types of oxime species, i.e., 4-morpholyl­carb­ami­doxime (hydroxy­guanidine), phenyl­acet­amidoxime and benzamidoxime (amidoximes), and cyclo­hexanone oxime and benzo­phenone oxime (ketoximes), react at room temperature with the 2-nitrilium closo-decaborate clusters, leading to 2-iminium closo-decaborates (14 examples; 57–94%). These species were characterized by ICPMS-based boron elemental analysis, HRESI–-MS, molar conductivity, IR, 1H­{11B}, and 11B­{1H} NMR spectroscopies, and additionally by single-crystal X-ray diffraction (for six compounds). On the basis of kinetic data, ΔH ⧧, ΔS ⧧, and ΔG ⧧ of the additions were determined, showing a 4 order-of-magnitude decrease in reactivity from the hydroxy­guanidine to the aromatic ketoxime as entering nucleophiles. The results of DFT calculations indicate that the mechanism for these reactions is stepwise and is realized through the formation of the orientation complex of the nitrone form, R2R3CN+­(H)­O–, of oximes with [B10H9­NCEt]−, giving further an acyclic intermediate (the rate-determining step), followed by proton migration, leading to the addition product. The calculated overall activation barrier for these transformations is consistent with the experimental kinetic observations. This work provides, for the first time, a broad nucleophilicity series of oximes, which is useful to control various nucleophilic additions of oxime species.

The nitrile complexes trans‐[PtCl2(RCN)2] (R=Et (NC1), tBu (NC2), Ph (NC3), p‐BrC6H4 (NC4)) and cis‐[PtCl2(RCN)2] (R=Et (NC5), tBu (NC6), Ph (NC7)) react with 1 equiv of the hydroxyguanidine OC4H8NC(=NOH)NH2 (HG) furnishing the mono‐addition products trans‐ and cis‐[PtCl2(RCN){NH=C(R)ON=C(NH2)NC4H8O}] (1–4 and 9–11; 7 examples; 54–74 % yield). Treatment of any of the nitrile complexes NC1–NC7 with HG in a 1:2 molar ratio generated the bis‐addition products trans‐ and cis‐[PtCl2{NH=C(R)ON=C(NH2)NC4H8O}2] (5–8 and 12–14; 7 examples; 69–89 % yield). The PtII‐mediated coupling between nitrile ligands and HG proceeds substantially faster than the corresponding reactions involving amid‐ and ketoximes and gives redox stable products under normal conditions. Complexes 1, 6⋅4 CH2Cl2, 7⋅4 CH2Cl2, 8⋅2 CH2Cl2, and NC4 were studied by X‐ray crystallography. Platinum(II) species 1–3, 10, 11, and especially 9, efficiently catalyze the hydrosilylation cross‐linking of vinyl‐terminated poly(dimethylsiloxane) and trimethylsilyl‐terminated poly(dimethylsiloxane‐co‐ethylhydrosiloxane) giving high‐quality thermally stable silicon resins with no structural defects. The usage of these platinum species as the catalysts does not require any inhibitors and, moreover, the complexes and their mixtures with vinyl‐ and trimethylsilyl‐terminated polysiloxanes are shelf‐stable in air.

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