[(acridine)BCl2]+ : A Borenium Cation That Is a Strong Boron- and Carbon-Based Lewis Acid
[(acridine)BCl2]+ : A Borenium Cation That Is a Strong Boron- and Carbon-Based Lewis Acid
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DOI：
10.1021/om400463r
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发表时间：
2013-11-25
期刊：
影响因子：
2.8
通讯作者：
Ingleson, Michael J.
中科院分区：
文献类型：
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作者：
Clark, Ewan R.;Ingleson, Michael J.
[(吖啶)BCl2][AlCl4]是通过用AlCl3从(吖啶)BCl3中提取卤化物来合成的。经计算，[(吖啶)BCl2](+)中C9位的氢阴离子亲和力比硼的氢阴离子亲和力大14 kcal mol(-1)。 [(吖啶)BCl2][AlCl4]与1当量吖啶反应形成应变硼阳离子[(吖啶)(2)BCl2][AlCl4]，并通过光诱导单电子转移与P(异三叉基)(3)反应，通过自由基偶联形成9,9'-双吖啶烷部分。 [(吖啶)BCl2][AlCl4]和2,4,6-三叔丁基吡啶(TBP)结合形成稳定的受阻路易斯对(FLP)，在100℃下异解活化H-2。H-2活化产生的氢化物的最终位置是吖啶的C9位，而不是硼。当将噻吩并[3,2-b]噻吩添加到[(吖啶)BCl2][AlCl4]/TBP FLP或[(吖啶)(2)BCl2][AlCl4]中时，也会发生基于碳路易斯酸的反应，并且在两者中都观察到吖啶在C9处的芳基化。
[(acridine)BCl2][AlCl4] was synthesized by halide abstraction from (acridine)BCl3 with AlCl3. The hydride ion affinity of the C9 position in [(acridine)BCl2](+)was calculated to be 14 kcal mol(-1) greater than that at boron. [(acridine)BCl2][AlCl4] reacts with 1 equiv of acridine to form the strained boronium cation [(acridine)(2)BCl2][AlCl4] and with P(mesityl)(3) by photoinduced one-electron transfer to form the 9,9'-biacridane moiety by radical coupling. A stable frustrated Lewis pair (FLP) was formed on combining [(acridine)BCl2][AlCl4] and 2,4,6-tri-tert-butylpyridine (TBP), which heterolytically activated H-2 at 100 degrees C. The ultimate location of the hydride from H-2 activation was the C9 position of acridine and not boron. Carbon Lewis acid based reactivity also occurred when thieno[3,2-b]thiophene was added to the [(acridine)BCl2][AlCl4]/TBP FLP or to [(acridine)(2)BCl2][AlCl4], with arylation of acridine at C9 observed for both.