阴离子可以对蛋白质结构的溶解度和折叠产生显着影响,从而由于众所周知的霍夫迈斯特效应而改变其活性和稳定性。在此,我们报道了一种类蛋白质变构金属有机笼(MOC-68),其溶解度和构象通过阴离子交换调节,导致松弛状态(R状态)和紧张状态(T状态)之间的转换显示出独特的主客互动。这种构象变化使得无环烯烃分子间[2+2]光环加成的变构催化能够大大提高产率和非对映选择性。动力学实验表明,MOC-68 的 T 态对于空间和热力学不利的syn -HH 产物具有优越的催化性能,其速率比 R 态提高了三倍,并且由于反应加速而总共提高了七倍酶促笼效应。值得注意的是,这种变构笼表现出卓越的稳定性和可回收性,在五个循环中保持一致的催化效率和选择性。这项工作突出了柔性笼中结构变构在增强底物结合能力和催化选择性方面的潜力,为将模拟酶笼催化发展为可调节和高效的变构催化提供了一种方法。
Photosensitised regioselective [2+2]-cycloaddition of cinnamates and related alkenes
作者:Santosh K. Pagire、Asik Hossain、Lukas Traub、Sabine Kerres、Oliver Reiser
DOI:10.1039/c7cc06710k
日期:——
An efficient method for the synthesis of substituted cyclobutanes from cinnamates, chalcones, and styrenes has been developed utilizing a visible-light triplet sensitisation mode. This reaction provides a diverse range of substituted cyclobutanes in high yields under mild conditions without the need of external additives. Good regioselectivity is obtained due to strong π–π-stacking of arene moieties
Heteroleptic copper(I) complexes as energy transfer photocatalysts for the intermolecular [2 + 2] photodimerization of chalcones, cinnamates and cinnamamides
作者:Qing-An Wu、Chen-Chao Ren、Feng Chen、Tian-Qi Wang、Yu Zhang、Xue-Fen Liu、Jian-Bin Chen、Shu-Ping Luo
DOI:10.1016/j.tetlet.2021.153091
日期:2021.5
The [2 + 2] photodimerization of chalcones, cinnamates and cinnamamides can be effectively catalyzed by heteroleptic copper(I) complexes. The reactions were carried out under mild reaction conditions and the products were obtained in 20–72% yield under visible light irradiation. The copper-based photocatalyst comprised of the rigid phenanthroline ligand with substituents at the 2,9-positions and the
MOC-68 is superior in catalytic performance for the steric and thermodynamic unfavored syn-HH product, displaying a threefold rate enhancement over the R-state and totally a sevenfold increase owing to the reaction acceleration contributed by an enzymatic cage effect. Notably, this allosteric cage exhibits exceptional stability and recyclability, maintaining consistent catalytic efficiency and selectivity
阴离子可以对蛋白质结构的溶解度和折叠产生显着影响,从而由于众所周知的霍夫迈斯特效应而改变其活性和稳定性。在此,我们报道了一种类蛋白质变构金属有机笼(MOC-68),其溶解度和构象通过阴离子交换调节,导致松弛状态(R状态)和紧张状态(T状态)之间的转换显示出独特的主客互动。这种构象变化使得无环烯烃分子间[2+2]光环加成的变构催化能够大大提高产率和非对映选择性。动力学实验表明,MOC-68 的 T 态对于空间和热力学不利的syn -HH 产物具有优越的催化性能,其速率比 R 态提高了三倍,并且由于反应加速而总共提高了七倍酶促笼效应。值得注意的是,这种变构笼表现出卓越的稳定性和可回收性,在五个循环中保持一致的催化效率和选择性。这项工作突出了柔性笼中结构变构在增强底物结合能力和催化选择性方面的潜力,为将模拟酶笼催化发展为可调节和高效的变构催化提供了一种方法。