Boryllithium: Isolation, Characterization, and Reactivity as a Boryl Anion
Boryllithium: Isolation, Characterization, and Reactivity as a Boryl Anion
复制标题
DOI：
10.1126/science.1131914
复制
发表时间：
2006-10
期刊：
影响因子：
56.9
通讯作者：
Yasutomo Segawa;M. Yamashita;K. Nozaki
中科院分区：
文献类型：
--
作者：
Yasutomo Segawa;M. Yamashita;K. Nozaki
亲核，阴离子硼基化合物是长期寻找但难以捉摸的物种。我们报道了N，N ' -双（2,6-二异丙基苯基）-2-溴-2,3-二氢- 1h -1,3,2-重氮硼环的硼溴键被萘化锂还原裂解得到相应的硼锂，该硼锂与N-杂环碳具有等电子关系。x射线晶体学分析表明硼锂的结构符合sp2硼杂化，硼锂键长为2.291±0.006埃。该化合物与计算得到的游离硼基阴离子结构相似，表明硼原子带有阴离子电荷。11B核磁共振谱也支持硼基阴离子的特征。此外，该化合物在与亲电试剂如水、三氟甲烷磺酸甲酯、1-氯丁烷和苯甲醛的反应中表现为有效的碱和亲核试剂。
Nucleophilic, anionic boryl compounds are long-sought but elusive species. We report that reductive cleavage of the boron-bromine bond in N,N′-bis(2,6-diisopropylphenyl)-2-bromo-2,3-dihydro-1H-1,3,2-diazaborole by lithium naphthalenide afforded the corresponding boryllithium, which is isoelectronic with an N-heterocyclic carbene. The structure of the boryllithium determined by x-ray crystallography was consistent with sp2 boron hybridization and revealed a boron-lithium bond length of 2.291 ± 0.006 angstroms. The structural similarity between this compound and the calculated free boryl anion suggests that the boron atom has an anionic charge. The 11B nuclear magnetic resonance spectrum also supports the boryl anion character. Moreover, the compound behaves as an efficient base and nucleophile in its reactions with electrophiles such as water, methyl trifluoromethanesulfonate, 1-chlorobutane, and benzaldehyde.