Isoselective Lactide Ring Opening Polymerisation using [2]Rotaxane Catalysts
作者:Jason Y. C. Lim、Nattawut Yuntawattana、Paul D. Beer、Charlotte K. Williams
DOI:10.1002/anie.201901592
日期:2019.4.23
properties depend upon its stereochemistry and isotactic PLA shows superior thermal‐mechanical performances. Here, a new means to control tacticity by exploiting rotaxane conformational dynamism is described. Dynamic achiral [2]rotaxanes can show high isoselectivity (Pi=0.8, 298 K) without requiring any chiral additives and enchain by a chain end control mechanism. The organocatalytic dynamic stereoselectivity
聚乳酸(PLA)是一种完全可生物降解和可回收的塑料,由生物衍生的单体制成:它是一种循环经济型塑料。它的性质取决于其立体化学,等规聚乳酸显示出优异的热机械性能。在这里,描述了一种通过利用轮烷构象动力学来控制战术性的新手段。动态的非手性[2]轮烷可以显示出较高的等选择性(P i = 0.8,298 K),而无需任何手性添加剂,并且可以通过链端控制机制进行链合。有机催化的动态立体选择性可能适用于其他小分子和聚合催化剂。
A new protocol for rotaxane synthesis
作者:Stuart J Cantrill、David A Fulton、Matthew C.T Fyfe、J.Fraser Stoddart、Andrew J.P White、David J Williams
DOI:10.1016/s0040-4039(99)00555-9
日期:1999.5
A novel [2]rotaxane was synthesized when an aniline-bearing [2]pseudorotaxane—generated by the hydrogen bond-driven threading of a dibenzylammonium filament through the cavity of the macrocyclic polyether dibenzo[24]crown-8—was stoppered via reaction with a bulky isocycanate. Complete characterization of the [2]rotaxane was accomplished by NMR spectroscopy, mass spectrometry and X-ray crystallography