Supramolecular synthesis of coumarin derivatives catalyzed by a coordination-assembled cage in aqueous solution

• 来源期刊: 中国科学:化学（英文版）
• 年，卷（期）: 2019,（6）
• 页码范围: 713-718
• 页数: 6页
• 语种: 英文

摘要

A self-assembled Pd4L2 cage is employed as a water-soluble molecular flask for the synthesis of functionalized coumarins from a series of salicylaldehyde derivatives and cyanoacetates/malononitrile.The catalytic reaction features mild aqueous conditions and broad substrate scope.Crystal structures of the host-guest complexes for two substrates and one analogous intermediate have been obtained,shedding light on the supramolecular reaction mechanism.Michaelis-Menten kinetic studies were performed in one typical case,revealing that the rate of product formation has been enhanced by over 23-fold in contrast to the background reaction without cage.Moreover,the same reaction catalyzed by a smaller Pd6L4 cage gives a mixture of products and much lower yields,suggesting that fine-tuning on the size and symmetry of the cages' cavity is crucial for their applications in supramolecular catalysis.