Article
Chemistry, Organic
Marina Perez-Palau, Nil Sanosa, Pedro Romea, Felix Urpi, Rosa Lopez, Enrique Gomez-Bengoa, Merce Font-Bardia
Summary: A new stereoselective alkylation method has been developed using titanium(IV) enolates of chiral N-acyl oxazolidinones with tert-butyl peresters from Ca-branched aliphatic carboxylic acids. The reaction proceeds through the decarboxylation of peresters and formation of alkyl radicals, resulting in alkylated adducts with excellent diastereoselectivity. Theoretical calculations explain the observed reactivity and outstanding stereocontrol, with the resulting compounds easily converted into ligands for asymmetric and catalytic transformations.
Article
Chemistry, Multidisciplinary
Yan-Bo Li, Hu Tian, Shuai Zhang, Jun-Zhao Xiao, Liang Yin
Summary: In this study, a copper(I)-catalyzed reaction of diarylphosphines and O-benzoyl hydroxylamines was developed, leading to the synthesis of aminophosphinites and P-chiral aminophosphinites. The reaction mechanism was proposed and further transformation to P-chiral phosphines was achieved.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Donglei Wang, Ying-Bo Shao, Yunrong Chen, Xiao-Song Xue, Xiaoyu Yang
Summary: An efficient method for the asymmetric synthesis of planar-chiral macrocycles (paracyclophanes) has been developed using chiral phosphoric acid catalysis for enantioselective electrophilic aromatic aminations with azodicarboxylates. This method allows for the synthesis of a wide range of chiral macrocycles with varying ring sizes and functional groups, achieving high yields and enantioselectivities. The mechanism and origins of the stereoselectivities of these reactions were investigated through experimental studies and computational calculations. Preliminary utilization of the planar-chiral macrocycle as a chiral organocatalyst demonstrated the potential applications of these novel chiral skeletons.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Lingpu Meng, Jingjie Yang, Mei Duan, You Wang, Shaolin Zhu
Summary: Regio- and enantioselective hydroarylamination, hydroalkylamination and hydroamidation of styrenes have been developed using NiH catalysis with a simple bioxazoline ligand under mild conditions. A variety of enantioenriched benzylic arylamines, alkylamines and amides can be easily accessed by employing nitroarenes, hydroxylamines and dioxazolones as amination reagents. Chiral induction in these reactions is proposed to proceed through an enantiodifferentiating syn-hydronickellation step.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Physical
Zeng Gao, Chao-Xian Yan, Jinlong Qian, Huameng Yang, Panpan Zhou, Jinlong Zhang, Gaoxi Jiang
Summary: An efficient and rapid method for constructing a family of axially chiral sulfonamides with a wide functional group tolerance has been developed through Pd-catalyzed atroposelective hydroamination. Simple oxidation and gamma-addition enabled the synthesis of various valuable axially chiral sulfonamides and anilides, including non-natural amino acid derivatives. Preliminary DFT calculations were used to explain the origin of asymmetric induction.
Article
Chemistry, Organic
Wen-Cheng Li, Lei Yang, Zhong-Lin Wei, Wei-Wei Liao
Summary: A straightforward diastereo- and enantioselective Claisen rearrangement/oxa-Michael addition tandem sequence with a cinchona squaramide catalyst was developed for the synthesis of valuable dihydropyrans. The organo-bifunctional catalyst played a crucial role in enhancing the stereoselectivity in this asymmetric tandem sequence. Additionally, good yields and moderate stereoselectivities were achieved in the asymmetric catalytic sequential processes of hydroalkoxylation/Claisen rearrangement/cyclization and Claisen rearrangement/aza-Michael addition tandem sequences.
Article
Chemistry, Applied
Raja K. K. Rit, Hongyi Li, Stephen P. P. Argent, Katherine M. M. Wheelhouse, Simon Woodward, Hon Wai Lam
Summary: Chiral dienes are important ligands in asymmetric catalysis but they are difficult to obtain. In this study, a simple chiral allenecarboxanilide was used to produce pseudoenantiomeric bicyclo[2.2.2]octa-2,5-dienes containing an alkenyl bromide via intramolecular [4+2] cycloaddition. These compounds can be easily functionalized to provide diverse chiral diene ligands. The synthesis is straightforward and can be conducted on a large scale. The resulting ligands exhibit high performance in nine types of enantioselective Rh(I)-catalyzed addition reactions.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Chemistry, Physical
Cornelius V. Gaertner, Christoph Schneider
Summary: Chiral diphosphane Pd-aqua complexes have been used as efficient cooperative Bronsted acid-base catalysts in asymmetric transformations for the past 25 years. By deprotonating beta-dicarbonyl compounds, they readily form reactive chiral Pd enolates, while a Bronsted acid released from the catalyst activates the electrophile. After a period of dormancy, new developments in the enantioselective synthesis of heterocycles and other useful compounds have recently emerged, utilizing the unique properties of chiral Pd-aqua complexes.
Article
Chemistry, Multidisciplinary
Fengwei Chang, Chengyi Wang, Qipeng Chen, Yongjin Zhang, Guohua Liu
Summary: The combination of biocatalysis and transition-metal catalysis can bridge synthetic gaps in chemical or biological processes, but the deactivation between enzymatic and chemical species poses a significant challenge. Researchers developed an encapsulated Au/carbene and free amine dehydrogenase co-catalyst system, enabling efficient hydration/amination enantioselective cascade reaction.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Organic
David Weinzierl, Magdalena Piringer, Paul Zebrowski, Lotte Stockhammer, Mario Waser
Summary: Enantioselective synthesis of alpha-chlorinated carboxylic acid esters was achieved with er up to 99:1 and yields up to 82% via a one-pot multistep protocol starting from alpha-diazoketones. This process involves a photochemical Wolff rearrangement, enantioselective alpha-chlorination using a chiral Lewis base catalyst, and a final nucleophilic displacement of the bound catalyst. The resulting products were successfully used for stereospecific nucleophilic displacement reactions with N- and S-nucleophiles.
Article
Multidisciplinary Sciences
Yao Tang, Yu Wang, Qingkai Yuan, Sai Zhang, Jia-Yin Wang, Shengzhou Jin, Ting Xu, Junyi Pan, Kazimierz Surowiec, Guigen Li
Summary: There have been four methods documented in literature and textbooks for chirality control, including the use of chiral auxiliaries, reagents, solvents, and catalysts. This report presents a new type of asymmetric control, namely asymmetric catalysis via chiral aggregates, which is not classified under the aforementioned methods. The strategy involves the catalytic asymmetric dihydroxylation reaction of olefins using chiral ligands that aggregate in aggregation-induced emission systems. The work shows enhanced chiral induction by changing the ratios of the cosolvents tetrahydrofuran and H2O.
Article
Chemistry, Multidisciplinary
Yanhua Hu, Yashi Zou, Huiwen Yang, Haotian Ji, Yue Jin, Zhenfeng Zhang, Yangang Liu, Wanbin Zhang
Summary: Asymmetric sequential hydrogenations of conjugated enynes have been developed using a Ph-BPE-Co-I catalyst for the precise synthesis of chiral Z-allylamides with high activity and excellent enantioselectivity. The difference in catalytic activity between cobalt complexes of Ph-BPE and QuinoxP* was explained by the process decomposition of rate-determining step in the second hydrogenation.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Review
Chemistry, Organic
Dezheng Xie, Ziyi Chen, Chun-Jiang Wang, Xiu-Qin Dong
Summary: Phosphonates and derivatives with an α-chiral center are important compounds found in natural products, pharmaceuticals, and agrochemicals. The synthesis of these compounds has been the focus of recent research, with advancements in asymmetric catalysis such as hydrogenation, addition reactions, and nucleophilic additions to α,β-unsaturated phosphonates. The continuous development of enantioselective catalytic methods and the future applications of these compounds are also discussed.
SYNTHESIS-STUTTGART
(2023)
Article
Chemistry, Physical
Jian-Hua Liu, Qing Zhou, Yao Lin, Zhu-Lian Wu, Tian Cai, Wei Wen, Yan-Min Huang, Qi-Xiang Guo
Summary: In this study, a highly efficient atom-economic asymmetric alpha-allylation method using chiral-aldehyde/palladium catalyst was reported. This method enables the asymmetric alpha-allylation of different 1,3-dienes and allenes with N-unprotected amino acid esters, leading to the synthesis of alpha,alpha-disubstituted chiral alpha-amino acid esters with high efficiency, good yields, and stereoselectivities. No N-allylation byproducts were observed in these reactions. Two reaction models were proposed based on mechanistic control experiments. Overall, this work demonstrates a new approach for preparing structurally diverse chiral amino acids and provides insights for developing chiral-aldehyde catalytic systems.
Editorial Material
Chemistry, Multidisciplinary
Bing Fang, Yixuan Li, Fazheng Ren
Summary: In a recent Nature paper, Xu et al. reported the synthesis of chiral Au nanoparticles with the highest g-factor value. These chiral nanoparticles can regulate immune cell maturation, opening up the possibility of using nano scale chirality as an adjuvant for vaccines.