Umpolung of B-H Bonds by Metal-Ligand Cooperation with Cyclopentadienone Iridium Complexes
Umpolung of B-H Bonds by Metal-Ligand Cooperation with Cyclopentadienone Iridium Complexes
复制标题
环戊二烯酮铱配合物金属配体合作对 B-H 键的还原
DOI：
10.1002/anie.202011322
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
K. Nozaki
中科院分区：
文献类型：
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作者：
T. Higashi;S. Kusumoto;K. Nozaki
与传统的金属-配体协同裂解B−H键（在配体上提供B阳离子，在金属上提供H阴离子）相反，我们在本文中报道了新型环烯酮铱配合物对B−H键的uppolung。4，4，5，5-四甲基-1，3，2-二氧硼杂环戊烷（HBpin）和1，8-萘二胺硼烷（HBdan）的B−H键断裂，分别在金属离子和酚氧原子上生成一个阳离子。通过DFT计算的机理研究表明，烷氧羰基取代的环烯酮配体促进了B−H键氧化加成后的Ir−H去质子化，得到了umpolung产物。发现所产生的硼铱络合物在碱的存在下进行烯丙基卤的硼化，从而显示硼原子的亲核性质。
In contrast to conventional metal–ligand cooperative cleavage of a B−H bond, which provides a B cation on the ligand and an H anion on the metal, we report herein the umpolung of B−H bonds by novel cyclopentadienone iridium complexes. The B−H bonds of 4,4,5,5‐tetramethyl‐1,3,2‐dioxaborolane (HBpin) and 1,8‐naphthalenediaminatoborane (HBdan) were cleaved to give a Banionon the metal and an Hcationon the phenolic oxygen atom of the ligand. Mechanistic investigation by DFT calculations revealed that the alkoxycarbonyl‐substituted cyclopentadienone ligand facilitated deprotonation from Ir−H after oxidative addition of the B−H bond to give the umpolung product. The generated boryliridium complex was found to undergo borylation of an allyl halide in the presence of base, thus showing the nucleophilic nature of the boron atom.