Department of Molecular Sciences, Macquarie University, North Ryde, NSW 2109, Australia.
Dalton Trans. 2019 Oct 7;48(37):13989-13999. doi: 10.1039/c9dt02819f. Epub 2019 Sep 2.
The catalytic alkylation of ketones with alcohols via the hydrogen borrowing methodology (HB) has the potential to be a highly efficient approach for forming new carbon-carbon bonds. However, this transformation can result in more than one product being formed. The work reported here utilises bidentate triazole-carbene ligated iridium and rhodium complexes as catalysts for the selective formation of alkylated ketone or alcohol products. Switching from an iridium centre to a rhodium centre in the complex resulted in significant changes in product selectivity. Other factors - base, base loading, solvent and reaction temperature - were also investigated to tune the selectivity further. The optimised conditions were used to demonstrate the scope of the reaction across 17 ketones and 14 alcohols containing a variety of functional groups. A series of mechanistic investigations were performed to probe the reasons behind the product selectivity, including kinetic and deuterium studies.
酮与醇的氢借法（HB）催化烷基化反应有可能成为形成新的碳-碳键的高效方法。然而，这种转化可能会导致形成不止一种产物。这里报道的工作利用双齿三唑-卡宾配位的铱和铑配合物作为催化剂，选择性地形成烷基化酮或醇产物。将配合物中的铱中心转换为铑中心，导致产物选择性发生显著变化。其他因素-碱、碱负载量、溶剂和反应温度-也被研究以进一步调整选择性。优化条件用于在 17 个酮和 14 个含有各种官能团的醇中展示反应的范围。进行了一系列的机理研究来探究产物选择性的原因，包括动力学和氘研究。
