Cavity-directed synthesis within a self-assembled coordination cage: highly selective [2 + 2] cross-photodimerization of olefins.
Cavity-directed synthesis within a self-assembled coordination cage: highly selective [2 + 2] cross-photodimerization of olefins.
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DOI：
10.1021/ja020718
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发表时间：
2003-02
影响因子：
15
通讯作者：
M. Yoshizawa;Yoshihisa Takeyama;T. Okano;M. Fujita
中科院分区：
文献类型：
--
作者：
M. Yoshizawa;Yoshihisa Takeyama;T. Okano;M. Fujita
本文报道的是烯烃在自组装的配位笼中的高度选择性[2 + 2]的交叉二聚化，该蛋白在水性培养基中充当分子瓶。 M（6）L（4）协调纳米层，从六个PD（II）配合物和四个三齿配体的自组合可容纳两种不同类型的大烯烃分子，例如甲基磷酸乙二醇和5-乙氧基二磷酸酮，以一对选择的方式。这种前提识别模式使烯烃内烯烃的选择性[2 + 2]横二聚二聚化成为可能。在反应速率，立体选择性以及最重要的是成对选择性方面，该反应非常有效。在普通条件下在光化学上本身无活性的马来酰亚胺衍生物也非常有效地用乙二阳或二苯并贝贝贝嫩烯跨化。这些结果与有机培养基中常见光二聚化的结果形成了鲜明的对比，在这种培养基中，产量和选择性通常很差至中度。跨二聚体独家形成的关键步骤源于辐照前的三元络合物的选择性形成，该形成受客人与腔体密闭空间的尺寸兼容性的控制。
Herein reported is the highly selective [2 + 2] cross-photodimerization of olefins within a self-assembled coordination cage that acts as a molecular flask in an aqueous medium. An M(6)L(4) coordination nanocage that self-assembles from six Pd(II) complexes and four tridentate ligands accommodates two different kinds of large olefin molecules such as acenaphthylene and 5-ethoxynaphthoquinone in a pairwise selective fashion. This prerequisite recognition mode makes possible the selective [2 + 2] cross-photodimerization of the olefins within the cavity. The reaction is extremely efficient in terms of reaction rate, stereoselectivity, and, most importantly, pairwise selectivity. Maleimide derivatives, which themselves are photochemically inactive under ordinary conditions, are also cross-dimerized with acenaphthylene or dibenzosuberenon quite efficiently. These results are in sharp contrast to those of common photodimerization in organic media, where the yields and selectivities are generally poor to moderate. The key step of the exclusive formation of the cross-dimers stems from the selective formation of ternary complexes before irradiation, which is governed by the size compatibility of the guests with the confined space of the cavity.