尽管已经报道了一些关于轮烷的反应,但几乎没有研究轮烷提供独特反应场的特征,特别是作为催化剂。在我们对轮烷和链烷等互锁分子的持续研究中,我们注意到这种具有高自由度的互锁结构在分子催化剂等功能化材料中的重要性。对于催化不对称安息香缩合反应,使用联萘基团作为手性助剂制备了两种具有噻唑鎓盐部分的旋光轮烷。由手性轮烷作为催化剂催化的芳香醛的安息香缩合反应得到光学活性的安息香。取决于轮烷的结构和所采用的反应条件,30% ee 的中等至高化学产率。从结果来看,确认了两种轮烷内手性转移:(i)从轮到轴的空间手性转移和(ii)通过非手性轮控制的键合手性转移。由于这些不对称反应场是轮烷结构所特有的,因此在这项工作中证明了“轮烷场”作为特定反应场的重要性和可能性。
A bifunctionalized [3]rotaxane and its incorporation into a mechanically interlocked polymer
作者:Yi Jiang、Jia-Bin Guo、Chuan-Feng Chen
DOI:10.1039/c0cc00999g
日期:——
A novel bifunctionalized [3]rotaxane based on a triptycene-derived macrotricyclic host was conveniently synthesized. On the basis of the [3]rotaxane, a linear main-chain poly[3]rotaxane was further obtained by the highly efficient Huisgen 1,3-dipolar cycloaddition.
We report an efficient palladium-catalyzed approach to the synthesis of benzoxazole derivatives via sequential heteroarylation/acylation reaction of iodobenzenes. Three readily available starting materials, iodobenzenes, anhydrides, and benzoxazoles, were smoothly coupled to form new C–C bonds at the ortho and ipso positions of the iodobenzenes to afford 2-heteroaryl-3-acylbenzene derivatives in good
Sequential <i>O</i>- and <i>N</i>-Acylation Protocol for High-Yield Preparation and Modification of Rotaxanes: Synthesis, Functionalization, Structure, and Intercomponent Interaction of Rotaxanes
catalyst to afford the corresponding rotaxane in high yield. Large-scale synthesis without chromatographic separation was easily achieved. The ammonium group in the resulting rotaxane was quantitatively acylated with excess electrophile in the presence of excess trialkylamine. Various N-functionalized rotaxanes were prepared by this sequential double-acylation protocol. 1H NMR spectra and X-ray crystallographic
在三丁基膦作为催化剂的存在下,由庞大的酸酐将由24元冠醚和在末端带有羟基的仲铵盐组成的拟轮烷定量酰化,从而以高收率得到相应的轮烷。无需色谱分离即可轻松实现大规模合成。在过量的三烷基胺存在下,用过量的亲电子试剂将所得轮烷中的铵基团定量酰化。通过该顺序的双酰化方案制备了各种N-官能化的轮烷。1个轮烷的1 H NMR光谱和X射线晶体学分析表明,冠状醚组分通过强的氢键键合相互作用而被捕获在铵型轮烷中的铵基上。铵基周围的构象通过氢键相互作用而固定。同时,酰胺型轮烷的构象由冠醚中的亚甲基与车轴组件的苯环之间的弱CH /π相互作用确定。铵型轮烷的N-酰化可用于制备功能化的轮烷和弱的基于组分间相互作用的轮烷。
P<sup>III</sup>
-Chelation-Assisted Indole C7-Arylation, Olefination, Methylation, and Acylation with Carboxylic Acids/Anhydrides by Rhodium Catalysis
作者:Xiaodong Qiu、Panpan Wang、Dingyi Wang、Minyan Wang、Yu Yuan、Zhuangzhi Shi
DOI:10.1002/anie.201813182
日期:2019.1.28
olefination, and methylation of indoles with carboxylic acids or anhydrides by C−H and C−C bond activation have been developed. Furthermore, C7‐acylation products can also be generated selectively at a lower reaction temperature in the developed system. The key to the high reactivity and regioselectivity of this transformation is the appropriate choice of an indole N‐PtBu2 chelation‐assisted group
A convenient method has been developed, which allows for the direct transformation of aryl iodides into the corresponding carboxylic acid anhydrides viaPd-catalyzed carbonylation under atmospheric CO pressure.