Bimolecular Reaction via the Successive Introduction of Two Substrates into the Crystals of Networked Molecular Cages
Bimolecular Reaction via the Successive Introduction of Two Substrates into the Crystals of Networked Molecular Cages
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DOI：
10.1021/ja209290t
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发表时间：
2011-12-14
影响因子：
15
通讯作者：
Fujita, Makoto
中科院分区：
文献类型：
--
作者：
Inokuma, Yasuhide;Kojima, Nodoka;Fujita, Makoto
将两种底物 4-羟基二苯胺 (3) 和异氰酸乙酯 (4) 相继引入到网状 M6L4 笼 1 的晶体中。由于封装效应，在浸泡在 4 的溶液中时，大部分最初引入的底物 3 仍保留在晶体内。X 射线分析表明，在反应前，3 的亲核 NH 基团受到紧密保护。 堆积在笼单元内，同时 OH 基团暴露于进入的第二底物。将 4 连续引入晶体中会导致 3 在亲核性较低的 OH 基团处发生化学选择性酰化。观察到的化学选择性与溶液中离散的 M6L4 笼 2 所表现出的化学选择性一致。
Two substrates, 4-hydroxydiphenylamine (3) and ethyl isocyanate (4), were successively introduced into the crystals of networked M6L4 cages 1. Because of the encapsulation effect, most of the initially introduced substrate 3 remained within the crystals during immersion in a solution of 4. X-ray analysis revealed that before the reaction, the nucleophilic NH group of 3 is effectively protected by tight packing within the cage units while the OH group is exposed to the incoming second substrate. Successive introduction of 4 into the crystal results in the chemoselective acylation of 3 at the less nucleophilic OH group. The observed chemoselectivity is consistent with that exhibited by discrete M6L4 cage 2 in solution.