Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377 München, Germany.
J Am Chem Soc. 2010 May 5;132(17):6032-40. doi: 10.1021/ja908101j.
Solutions of allyl indium reagents formed in the reactions of indium with allyl bromide and allyl iodide, respectively, in N,N-dimethylformamide, tetrahydrofuran, and water were analyzed by a combination of electrospray-ionization mass spectrometry, temperature-dependent (1)H NMR spectroscopy, and electrical conductivity measurements. Additional mass spectrometric experiments probed charge-tagged derivatives of the allyl indium reagents. The results obtained indicate the presence of allyl indium(+3) species, which undergo heterolytic dissociation to yield ions such as InR(2)(solv)(+) and InRX(3)(-) with R = allyl and X = Br and I. The extent of dissociation is greatest for N,N-dimethylformamide, whereas aggregation effects are more pronounced for the less polar tetrahydrofuran. The heterolytic dissociation of the allyl indium reagents supposedly enhances their reactivity by simultaneously providing highly Lewis acidic allyl indium cations and nucleophilic allyl indate anions.
烯丙基铟试剂的解决方案分别在 N，N-二甲基甲酰胺、四氢呋喃和水中形成的与烯丙基溴和烯丙基碘的反应，通过电喷雾电离质谱、温度依赖性（1）H NMR 光谱和电导率测量的组合进行了分析。附加的质谱实验探测了烯丙基铟试剂的带电标记衍生物。所得结果表明存在烯丙基铟（+3）物种，其经历异裂解离以生成离子，例如 InR（2）（溶剂）+和 InRX（3）-与 R = 烯丙基和 X = Br 和 I。对于 N，N-二甲基甲酰胺，解离程度最大，而对于极性较小的四氢呋喃，聚集效应更为明显。烯丙基铟试剂的异裂解离通过同时提供高路易斯酸性的烯丙基铟阳离子和亲核性的烯丙基 indate 阴离子，从而增强了它们的反应性。
