One-Pot Synthesis of Aldehydes or Alcohols from CO2 via Formamides or Silyl Formates
One-Pot Synthesis of Aldehydes or Alcohols from CO2 via Formamides or Silyl Formates
复制标题
CO2 通过甲酰胺或甲硅烷基酯一锅法合成醛或醇
DOI：
10.1002/adsc.202300031
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发表时间：
2023
影响因子：
5.4
通讯作者：
Tadashi Ema
中科院分区：
文献类型：
--
作者：
Fan Yang;Yuta Saiki;Koichi Nakaoka;Tadashi Ema
在Cu（OAc）2催化下，2-（甲氨基）吡啶与CO2和苯基硅烷在无溶剂条件下发生N-取代反应，生成N-甲基-N-（2-吡啶基）甲酰胺，称为Comins-Meyers甲酰胺。铜配合物的X射线晶体学分析揭示了由两个铜离子通过四个乙酸根离子桥连的桨轮结构，其中两个分子的2-（甲氨基）吡啶在两个轴向位点上，这表明（i）铜离子的溶解度改善和（ii）乙酸根离子的亲核性增强用于苯基硅烷的活化。含有Cu-（0Ac）2、2-（甲基氨基）吡啶和苯基硅烷的苯-d 6溶液的1H NMR光谱显示在2.62ppm处的单重态信号，其归属于催化活性Cu 2 OH物质，并且该信号在暴露于CO2时消失。在无溶剂条件下，以2-（甲氨基）吡啶为原料，通过铜催化CO2硅氢加成反应合成了Comins-Meyers甲酰胺，然后在THF中直接进行Grignard反应，一锅法合成了醛或醇。另一方面，甲硅烷基甲酸酯由CO2和苯基硅烷使用四丁基乙酸铵（TBAA）作为有机催化剂制备的也被发现是很好的醇的前体。
The solvent-free N-formylation of 2-(methylamino) pyridine with CO2 and phenylsilane was catalyzed by Cu (OAc) 2 alone to give N-methyl-N-(2-pyridyl) formamide called Comins-Meyers formamide. The X-ray crystallographic analysis of a copper complex revealed a paddle-wheel structure consisting of two copper ions bridged by four acetate ions with two molecules of 2-(methylamino) pyridine on both axial sites, which suggested (i) the improved solubility of the copper ion and (ii) the enhanced nucleophilicity of the acetate ion for the activation of phenylsilane. 1H NMR spectra of benzene-d6 solutions containing Cu-(OAc) 2, 2-(methylamino) pyridine, and phenylsilane showed a singlet signal at 2.62 ppm, which was assigned to a catalytically active CuÀ H species, and this signal disappeared upon exposure to CO2. Comins-Meyers formamide synthesized from 2-(methylamino) pyridine via the copper-catalyzed hydrosilylation of CO2 under solvent-free conditions was directly subjected to the Grignard reactions in THF for the one-pot synthesis of aldehydes or alcohols. On the other hand, silyl formates prepared from CO2 and phenylsilane using tetrabutylammonium acetate (TBAA) as an organocatalyst were also found to be good precursors of alcohols.