Complex OsH₆(PⁱPr₃)₂ is an efficient catalyst precursor for the addition of pinacolborane and catecholborane to the C–N triple bond of alkyl nitriles. In this way, a variety of N,N-diborylamines have been isolated and fully characterized, including 13 derivatives not described so far. The range of nitriles used is wide and comprises substrates having unfunctionalized linear and branched chains, and functionalized chains with methoxide, trifluoromethyl, aryl, pyridyl, benzoyl, or cyanide groups. Kinetic studies demonstrate that the overall process consists of two consecutive irreversible reactions: the catalytic metal-promoted monohydroboration of the nitrile to afford the borylimine and the metal-free stoichiometric hydroboration of the latter to give the diborylamine. The mechanism of the hydroboration has been established by combining the kinetic analysis of the catalysis, stoichiometric reactions, and DFT calculations. The rate-determining step of the catalysis is the insertion of the C–N triple bond of the nitrile into the Os–B bond of an osmium-σ-borane intermediate and is regiodirected by the nucleophilicity of the nitrogen atom and the electrophilicity of the carbon atom of the nitrile.

中文翻译：

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Po催化的烷基腈二氢硼化：范围，动力学和机理。

复杂的OsH ₆（P ⁱ Pr ₃）₂是将频哪醇硼烷和儿茶酚硼烷添加到烷基腈的C-N三键上的有效催化剂前体。这样，各种N，N-二硼烷基胺已经被分离出来并被充分表征，包括迄今未描述的13种衍生物。所用腈的范围很广，包括具有未官能化的直链和支链以及具有甲醇盐，三氟甲基，芳基，吡啶基，苯甲酰基或氰化物基团的官能化链的底物。动力学研究表明，整个过程由两个连续的不可逆反应组成：腈催化的金属促进的单氢硼化反应制得硼氧嘧啶，而无金属的化学计量的硼氢化反应则制得二硼烷基胺。通过结合催化动力学分析，化学计量反应和DFT计算，建立了硼氢化反应的机理。