Regio- and Stereoselective Carbobismuthination of Alkynes
Regio- and Stereoselective Carbobismuthination of Alkynes
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DOI：
10.1002/anie.201107127
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发表时间：
2012-01-01
影响因子：
16.6
通讯作者：
Baba, Akio
中科院分区：
文献类型：
--
作者：
Nishimoto, Yoshihiro;Takeuchi, Midori;Baba, Akio
碳-碳三键的碳化作为烯基金属化合物的合成方法具有优异的价值，并且伴随着碳-碳键和碳-金属键的形成。因此，许多化学家开发了使用各种金属元素的碳化反应。[1]然而，据我们所知，从未有过碳铋中毒的报道。[2-4]许多无机铋化合物用于各种应用，包括作为医药化学品，因为铋是与其他重元素如砷，锑，铅和铊相比几乎无毒的重元素。[5]然而，有机铋化合物在合成化学中的应用主要限于通过芳基铋化合物引入芳基部分，[6]可能是因为其他有机铋化合物的实用合成方法很少。通常仅应用卤化铋和有机金属化合物之间的金属转移，因此限制了相容官能团的数量。[7]在此，我们希望报道第一个炔的碳铋化反应。与一般的碳化反应相反，单独引入碳亲核试剂和金属而不预先形成有机金属亲核试剂导致碳铋化[等式（1）]。此外，本研究是基于这一概念扩展碳金属化的努力，最近已报道用于碳氢化和碳氢化。[8，9]本发明的反应体系仅需要BiBr 3、炔和烯酮甲硅烷基缩醛的简单混合物，以产生具有高立体选择性和区域选择性的带有酯部分的烯基铋。BiBr 3与3，5-二（叔丁基）苯乙炔1和二甲基烯酮三甲基甲硅烷基甲基缩醛2在CH 2Cl 2中在室温下反应，以定量产率得到单烯基二溴化铋3，为白色固体[Eq.②]。x射线结晶学分析
The carbometalation of carbon–carbon triple bonds is of excellent value as a synthetic method for alkenylmetal compounds and is accompanied by the formation of both carbon–carbon and carbon–metal bonds. Therefore, carbometalations using a variety of metal elements have been developed by many chemists.[1] As far as we could ascertain, however, carbobismuthination has never been reported.[2–4] Many inorganic bismuth compounds are used in various applications, including as medicinal chemicals, because bismuth is a virtually nontoxic heavy element in contrast with other heavy elements such as arsenic, antimony, lead, and thallium.[5] However, the use of organobismuth compounds in synthetic chemistry has been mostly limited to the introduction of aryl moieties by an arylbismuth compound,[6] perhaps because practical synthetic methods of other organobismuth compounds are scarce. Only transmetalation between a bismuth halide and an organometallic compound has been generally applied, thus limiting the number of compatible functional groups.[7] Herein, we wish to report the first carbobismuthination of an alkyne. In contrast with general carbometalations, the separate introduction of a carbon nucleophile and a metal without the preformation of organometallic nucleophiles resulted in carbobismuthination [Eq (1)]. In addition, the present study was an effort to expand carbometalation based on this concept, which has recently been reported for carboindation and carbogallation.[8, 9] The present reaction system requires only a simple mixture of BiBr3, an alkyne, and a ketene silyl acetal to produce an alkenylbismuth bearing an ester moiety with high stereo-and regioselectivity.First, the achievement of a carbobismuthination was confirmed by X-ray crystallographic analysis of the alkenylbismuth compound. The reaction of BiBr3 with 3, 5-di (tertbutyl) phenylacetylene 1 and dimethylketene trimethylsilyl methyl acetal 2 in CH2Cl2 at room temperature gave monoalkenylbismuth dibromide 3 as a white solid in a quantitative yield [Eq.(2)]. X-ray crystallographic analysis