Chiral N-tert-butanesulfinyl α,β-unsaturated ketimine: a simple and highly effective olefin/sulfinimide hybrid ligand for asymmetric 1,4-additions
作者:Xiangqing Feng、Beibei Wei、Jing Yang、Haifeng Du
DOI:10.1039/c1ob05971h
日期:——
One novel type of chiral olefin/sulfinimide hybrid ligands has been developed through a simple one-step condensation of α,β-unsaturated ketones with tert-butanesulfinamide and utilized successfully for rhodium-catalyzedasymmetricconjugatedadditions to furnish the desired adducts in high yields with excellent ee's.
Chiral dihydrobenzofuran-based diphosphine (BICMAP): optical resolution and application to rhodium(I)-catalyzed asymmetric 1,4-addition of aryl- and alkenylboronic acids to cyclic enones
Chiral dihydrobenzofuran-based diphosphine ligand (BICMAP) 1 was used as a ligand for the rhodium(I)-catalyzed asymmetric1,4-addition of arylboronicacids to cyclic enones up to 99% ee. We also found that the BICMAP-rhodium system was an efficient catalyst for the 1,4-addition of alkenylboronic acids to 2-cyclohexenone in good enantioselectivities.
A dual-metal-catalyzed asymmetric [3+2] annulation of 2-vinyloxiranes with the challenging nucleophilic dipoles (imino esters) was achieved. It was successfully applied to the stereodivergent synthesis of structurally rigid spirocyclic framework. A series of spirocompounds bearing a pyrroline and an olefin were synthesized in an enantio- and diastereodivergent manner.
Three-Dimensional Homochiral Covalent Organic Frameworks with Intrinsic Chiral <b>qzd</b> Topology
作者:Xing Kang、Cheng Cheng、Xu Chen、Jinqiao Dong、Yan Liu、Yong Cui
DOI:10.1021/jacs.3c14230
日期:2024.3.27
framework materials have been reported, there are few examples known to combine molecular chirality, helicity, and three-dimensional (3D) intrinsically chiral topology in one structure, which is beneficial for chirality transfer and amplification. Here, we report the synthesis of the first two 3D covalentorganic frameworks (COFs) with an intrinsic chiral qzd topology, which exhibit unusual integration of
尽管已经报道了多种手性多孔骨架材料,但将分子手性、螺旋性和三维(3D)本质手性拓扑结合在一种结构中的例子很少,这有利于手性转移和放大。在这里,我们报告了前两个具有内在手性qzd拓扑结构的 3D 共价有机框架 (COF) 的合成,它们表现出各种同手性和同螺旋特征的不寻常整合。通过4-连接的卟啉四胺和2-连接的对映纯二烯二醛的亚胺缩合,我们制备了两种具有非互穿qzd拓扑结构的COF。 V 形二烯连接体的特定几何形状和构象灵活性控制具有旋转连接的方形平面卟啉单元的排列,并促进产生以卟啉螺旋排列为特征的同手性延伸多孔结构。 CCOF 23与 Rh(I) 的合成后金属化为芳基硼酸与 2-环己烯酮的不对称迈克尔加成反应提供了非均相催化剂,与均相对应物相比,其显示出更高的对映选择性,可能是由于螺旋通道的有限效应。这一发现将为探索多手性材料提供动力,为固态下螺旋性、同手性和对映选择性的生成和控制提供新的见解。
Polymer-Incarcerated Chiral Rh/Ag Nanoparticles for Asymmetric 1,4-Addition Reactions of Arylboronic Acids to Enones: Remarkable Effects of Bimetallic Structure on Activity and Metal Leaching
Robust and highly active bimetallic Rh nanoparticle (NP) catalysts, PI/CB Rh/Ag have been developed and applied to the asymmetric 1,4-addition of arylboronic acids to enones without leaching of the metals. We found that the structures of the bimetallic Rh/Ag catalysts and chiral ligands strongly affect their catalytic activity and the amount of metal leaching. PI/CB Rh/Ag could be recycled several times by simple operations while keeping high yields and excellent enantioselectivities. To show the versatility of the PI/CB Rh/Ag catalyst, a one-pot, oxidation-asymmetric 1,4-addition reaction of an allyl alcohol and an arylboronic acid was demonstrated by combining the PI/CB Rh/Ag catalyst with PI/CB Au as an aerobic oxidation catalyst.