Rigo Massimo, Hettmanczyk Lara, Heutz Frank J L, Hohloch Stephan, Lutz Martin, Sarkar Biprajit, Müller Christian
Institut für Chemie und Biochemie, Freie Universität Berlin, Fabeckstr. 34/36, 14195 Berlin, Germany.
EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, KY16 9ST, UK.
Dalton Trans. 2016 Dec 20;46(1):86-95. doi: 10.1039/c6dt03766f.
Gold(i) complexes based on a 2,4,6-triarylphosphinine and a mesoionic carbene derivative have been prepared and characterized crystallographically. Although structurally related, both heterocycles differ significantly in their donor/acceptor properties. These opposed electronic characteristics have been exploited in Au(i)-catalyzed cycloisomerization reactions. For the conversion of the standard substrate dimethyl 2-(3-methylbut-2-enyl)-2-(prop-2-ynyl)malonate the results obtained for both Au-catalysts were found to be very similar and comparable to the ones reported in the literature for other carbene- or phosphorus(iii)-based Au(i)-complexes. In contrast, a clear difference between the catalytic systems was found for the cycloisomerization of the more challenging substrate N-2-propyn-1-ylbenzamide. A combination of the phosphinine-based complex and [AgSbF] or [Cu(OTf)] leads to a catalytic species, which is more active than the mesoionic carbene-based coordination compound. We attribute these differences to the stronger π-accepting ability of phosphinines in comparison to mesoionic carbenes. The here presented results show for the first time that phosphinines can be used efficiently as π-accepting ligands in Au(i)-catalyzed cycloisomerization reactions.
基于2,4,6-三芳基膦腈和中氮茚卡宾衍生物的金（I）配合物已被制备并通过晶体学进行了表征。尽管在结构上相关，但这两种杂环在其供体/受体性质上有显著差异。这些相反的电子特性已被用于金（I）催化的环异构化反应中。对于标准底物2-（3-甲基丁-2-烯基）-2-（丙-2-炔基）丙二酸二甲酯的转化，发现两种金催化剂得到的结果非常相似，且与文献中报道的其他基于卡宾或磷（III）的金（I）配合物的结果相当。相比之下，对于更具挑战性的底物N-2-丙炔-1-基苯甲酰胺的环异构化，发现催化体系之间存在明显差异。基于膦腈的配合物与[AgSbF]或[Cu(OTf)]的组合产生了一种催化物种，其活性比基于中氮茚卡宾的配位化合物更高。我们将这些差异归因于膦腈相比中氮茚卡宾具有更强的π接受能力。本文首次展示的结果表明，膦腈可以有效地用作金（I）催化的环异构化反应中的π接受配体。
