Article
Chemistry, Organic
Meng-Cheng Zhang, Dong-Chao Wang, Gui-Rong Qu, Hai-Ming Guo
Summary: The first catalytic asymmetric route to synthesize chiral thiohydantoins containing a quaternary stereogenic center has been established using a chiral phosphoric acid catalyst, achieving high yields and excellent enantioselectivities. This reaction also allows for the construction of two C-N bonds.
ORGANIC CHEMISTRY FRONTIERS
(2022)
Article
Chemistry, Organic
Yakun Wang, Shuaifei Wang, Peiyong Qiu, Lizhen Fang, Ke Wang, Yawei Zhang, Conghui Zhang, Ting Zhao
Summary: An efficient and enantioselective alpha-electrophilic difluoromethylation of beta-keto esters has been achieved by phase-transfer catalysis, providing good enantioselectivities and yields with high C/O regioselectivities. The C/O selectivity of beta-keto esters can be easily reversed and controlled, offering a novel and efficient way for introducing chiral C-CF2H groups.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2021)
Article
Chemistry, Organic
Christopher Mairhofer, Victoria Haider, Thomas Bogl, Mario Waser
Summary: The deoxyfluorination of cyclic alpha-hydroxy-beta-ketoesters using DAST reported in this study demonstrates high levels of stereospecificity, resulting in the configurationally inverted alpha-fluoro-beta-ketoesters in high yields under simple operation conditions.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Vasco Corti, Riccardo Riccioli, Ada Martinelli, Sofia Sandri, Mariafrancesca Fochi, Luca Bernardi
Summary: This study presents a one-pot approach to enantioenriched beta-branched beta-trifluoromethyl alpha-amino acid derivatives, grounded on the reduction - ring opening of Erlenmeyer-Plochl azlactones. The configurations of the two chirality centers of the products are established during each of the two catalytic steps, enabling a stereodivergent process.
Review
Multidisciplinary Sciences
Ruixian Deng, Tian-Jiao Han, Xiang Gao, Yuan-Fu Yang, Guang-Jian Mei
Summary: beta,gamma-Unsaturated alpha-ketoesters are versatile organic synthons in catalytic asymmetric transformations. The highly efficient creation of stereogenic centers with excellent enantioselectivity is achieved through the bidentate coordination of their unique 1,2-dicarbonyl motif to chiral messengers. Various reaction modes of beta,gamma-Unsaturated alpha-ketoesters involving multiple reaction sites have been developed in the past five years. This review provides an updated overview for chemists working in this field, facilitating their discoveries in asymmetric catalysis, natural products synthesis, and drug development.
Article
Chemistry, Organic
Vasileios Giannopoulos, Ioulia Smonou
Summary: An enzymatic approach for the asymmetric reduction of alpha,alpha-dichloro-beta-keto esters has been developed, leading to the synthesis of enantiomerically pure (S)-alpha,alpha-dichloro-beta-hydroxy esters in a single step.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Zhenwei Wu, Suvratha Krishnamurthy, K. S. Satyanarayana Tummalapalli, Jun Xu, Caizhen Yue, Jon C. Antilla
Summary: A new catalytic synthesis method using chiral calcium phosphate has been developed to efficiently and selectively produce chiral alpha-amino-beta-keto ester derivatives with practicality and high catalytic efficiency.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Multidisciplinary
Nagaraju Sakkani, Dhiraj K. Jha, Emily Whatley, John C-G Zhao
Summary: In this study, the direct synthesis of alpha-acyloxylketones from ketones and readily available carboxylic acids was achieved using a photo-assisted halogen bond-mediated organocatalytic reaction. This method holds significance in the synthesis of pharmaceuticals and biologically active products.
CHEMICAL COMMUNICATIONS
(2022)
Article
Chemistry, Organic
Shinnosuke Kitayama, Hiroaki Shimizu, Satoshi Yokoshima
Summary: In this study, photoirradiation of alpha-(2-nitrophenyl)ketones resulted in the production of cyclic hydroxamates. The reaction involved photoinduced oxygen transfer from the nitro group to the benzylic position, leading to the formation of an alpha-hydroxyketone with a nitroso group. Subsequent addition of the nitroso group to the ketone moiety and the cleavage of the C-C sigma bond between the carbonyl group and the benzyl position produced hydroxamic acid, which then underwent hemiacetal formation to yield cyclic hydroxamate.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2022)
Article
Chemistry, Organic
Hong-Wei Chen, Qin-Hua Song
Summary: This study presents a direct regioselective benzoyloxylative dearomatization of alpha- and beta-naphthols by benzoyl peroxide in an air atmosphere, under radical inhibitor- and catalyst-free conditions, at room temperature. The methodology offers a new efficient strategy for the construction of alpha-ketol derivatives with oxo-quaternary carbon center from naphthols with good to excellent yields.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2021)
Article
Chemistry, Organic
Hualing He, Xiaoxue Tang, Yang Cao, Jon C. Antilla
Summary: A catalytic enantioselective reduction of alpha-trifluoromethylated imines has been developed using a BINOL-derived boro-phosphate as catalyst and catecholborane as hydride source. This method provides an efficient route to prepare synthetically useful chiral alpha-trifluoromethylated amines in high yields and excellent enantioselectivities under mild conditions (up to 98% yield and 96% ee).
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Zhichao Wang, Shoko Yamazaki, Tsumoru Morimoto, Hiroshi Takashima, Ayane Nakaoku, Makoto Shimizu, Akiya Ogawa
Summary: This study investigated intramolecular cyclization reactions of arylpropargyl amides of electron-deficient alpha, beta-alkenyl carboxylates, such as fumarates and ethenetricarboxylates. The reactions yielded benz[f]isoindoline derivatives when fumaramides were reacted with a base, Et3N or DBU, in xylenes under air. Aroyl-substituted pyrrolidine derivatives were obtained as major products when amides of fumarate and ethenetricarboxylate were heated in DMSO. The reaction mechanisms were discussed using density functional theory (DFT) calculations.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2023)
Article
Chemistry, Organic
Rui-Hao Liu, Guo-Li Chai, Xiao Wang, Hong-Yu Deng, Junbiao Chang
Summary: The asymmetric 1,3-dipolar cycloaddition reaction of beta-trifluoromethyl alpha,beta-unsaturated ketone with N,N'-cyclic azomethine imines was developed using a (R)-3,3'-(3,5-(CF3)2-C6H3)2-BINOL-boron complex catalyst. The reaction efficiently produces N,N'-bicyclic pyrazolidine derivatives with a stereogenic carbon center containing CF3 motifs in high yields and excellent diastereo- and enantioselectivities.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Qiupeng Peng, Bingjia Yan, Fangyi Li, Ming Lang, Bei Zhang, Donghui Guo, Donald Bierer, Jian Wan
Summary: An efficient method for obtaining a wide range of fluorinated products with high enantioselectivity was reported through enantioselective [1,3]-proton shift of beta,beta-difluoro-alpha-imine amides catalyzed by chiral quinine derivatives. Optically pure beta,beta-difluoro-alpha-amino acid derivatives were further obtained, which are highly valuable in the synthesis of fluoro peptides, fluoro amino alcohols, and other fluorine-containing molecules. Organocatalysed 1,3-proton shifts provide a pathway to chiral nonracemic fluorinated products with high enantiomeric ratio.
COMMUNICATIONS CHEMISTRY
(2021)
Article
Chemistry, Organic
Tanja Kaehler, Jonas Lorenz, Darren M. C. Ould, Dorothea Engl, Micol Santi, Lukas Gierlichs, Thomas Wirth, Rebecca L. Melen
Summary: A series of alpha-aryl or alpha-alkyl functionalised beta-hydroxy and beta-keto esters were successfully synthesized by reacting alpha-diazoesters with boranes, and aldehydes, ketones, anhydrides, nitriles, esters or isocyanates. The mild reaction protocol yielded 26 examples with up to 73% yield.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2022)
Article
Chemistry, Organic
Yakun Wang, Shuaifei Wang, Yufeng Wu, Ting Zhao, Jie Liu, Junlin Zheng, Lin Wang, Jieli Lv, Tao Zhang
Summary: We have developed a highly efficient enantioselective fluorination reaction of 4-substituted pyrazolones using amide-based Cinchona alkaloids catalysts. The reaction affords tetrasubstituted fluorine-attached chiral center products in high yields (up to 99%) and excellent enantioselectivities (up to 98% ee). Our method features low catalyst loading, short reaction times, and wide substrate scope. Furthermore, the reaction can be carried out under sustainable conditions for 10 cycles, and the optically pure product (>99.5% ee) can be easily obtained on a multigram scale through simple extraction and recrystallization. Controlled experiments and DFT studies revealed that the multiple hydrogen bonding interactions and steric hindrance contribute to the high enantioselectivity and reactivity. This transformation provides a practical method for the preparation of chiral fluorine-containing compounds with a simple operational protocol and low catalyst loading.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Organic
Yakun Wang, Shuaifei Wang, Peiyong Qiu, Lizhen Fang, Ke Wang, Yawei Zhang, Conghui Zhang, Ting Zhao
Summary: An efficient and enantioselective alpha-electrophilic difluoromethylation of beta-keto esters has been achieved by phase-transfer catalysis, providing good enantioselectivities and yields with high C/O regioselectivities. The C/O selectivity of beta-keto esters can be easily reversed and controlled, offering a novel and efficient way for introducing chiral C-CF2H groups.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2021)
Article
Chemistry, Organic
Yakun Wang, Yueyun Li, Mingming Lian, Jixia Zhang, Zhaomin Liu, Xiaofei Tang, Hang Yin, Qingwei Meng
ORGANIC & BIOMOLECULAR CHEMISTRY
(2019)
