School of Chemistry and Biochemistry, University of Geneva , Quai Ernest Ansermet 30, CH-1211 Geneva, Switzerland.
Departament de Química, Universitat de les Illes Balears , Carretera de Valldemossa km 7.5, 07122 Palma de Mallorca, Baleares, Spain.
J Am Chem Soc. 2017 Sep 27;139(38):13296-13299. doi: 10.1021/jacs.7b08113. Epub 2017 Sep 13.
Anion-π interactions on fullerenes are about as poorly explored as the use of fullerenes in catalysis. However, strong exchange-correlation contributions and the localized π holes on their surface promise unique selectivities. To elaborate on this promise, tertiary amines are attached nearby. Dependent on their positioning, the resulting stabilization of anionic transition states on fullerenes is shown to accelerate disfavored enolate addition and exo Diels-Alder reactions enantioselectively. The found selectivities are consistent with computational simulations, particularly concerning the discrimination of differently planarized and charge-delocalized enolate tautomers by anion-π interactions. Enolate-π interactions on fullerenes are much shorter than standard π-π interactions and anion-π interactions on planar surfaces, and alternative cation-π interactions are not observed. These findings open new perspectives with regard to anion-π interactions in general and the use of carbon allotropes in catalysis.
富勒烯上的阴离子-π 相互作用的研究还不如富勒烯在催化中的应用广泛。然而，强的交换相关贡献和其表面的局部化π 空穴有望带来独特的选择性。为了详细说明这一承诺，在附近连接了叔胺。根据它们的定位，证明富勒烯上阴离子过渡态的稳定化作用会加速不受欢迎的烯醇化物加成和外向 Diels-Alder 反应的对映选择性。发现的选择性与计算模拟一致，特别是关于阴离子-π 相互作用对不同平面化和电荷离域的烯醇互变异构体的区分。富勒烯上的烯醇化物-π 相互作用比标准的π-π 相互作用和平面表面上的阴离子-π 相互作用短得多，并且没有观察到替代的阳离子-π 相互作用。这些发现为阴离子-π 相互作用的一般性以及碳同素异形体在催化中的应用开辟了新的视角。
