Enantioselective Catalysis of the Aza-Cope Rearrangement by a Chiral Supramolecular Assembly
Enantioselective Catalysis of the Aza-Cope Rearrangement by a Chiral Supramolecular Assembly
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DOI：
10.1021/ja906386w
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发表时间：
2009-12-09
影响因子：
15
通讯作者：
Raymond, Kenneth N.
中科院分区：
文献类型：
--
作者：
Brown, Casey J.;Bergman, Robert G.;Raymond, Kenneth N.
手性超分子催化剂Ga4L6[L = 1,5-双(2,3-二羟基苯甲酰氨基)萘]是一种分子四面体，可催化烯丙基烯铵阳离子的3-aza-Cope重排。这种催化是通过在宿主内将底物预组织成反应性构象来实现的。这项工作表明，通过使用对映体纯组装，其手性空腔能够对映选择性地催化 3-aza-Cope 重排，在 50 °C 下产率可达 21−74%，对映体过量可达 6% 至 64%。在较低温度下，对映选择性得到改善，在 5 °C 时达到 78% ee。这是迄今为止由超分子组装体的手性空腔诱导的最高对映选择性。
The chiral supramolecular catalyst Ga4L6[L = 1,5-bis(2,3-dihydroxybenzoylamino)naphthalene] is a molecular tetrahedron that catalyzes the 3-aza-Cope rearrangement of allyl enammonium cations. This catalysis is accomplished by preorganizing the substrate in a reactive conformation within the host. This work demonstrates that through the use of enantiopure assembly, its chiral cavity is capable of catalyzing the 3-aza-Cope rearrangement enantioselectively, with yields of 21−74% and enantiomeric excesses from 6 to 64% at 50 °C. At lower temperatures, the enantioselectivity improved, reaching 78% ee at 5 °C. This is the highest enantioselectivity to date induced by the chiral cavity of a supramolecular assembly.