Article
Chemistry, Multidisciplinary
Yair Cohen, Andre U. Augustin, Laura Levy, Peter G. Jones, Daniel B. Werz, Ilan Marek
Summary: The regio- and diastereoselective copper-catalyzed carbomagnesiation reaction of cyclopropenes provides an easy and efficient access to novel persubstituted cyclopropyl cores with complete regio- and diastereoselectivity, despite the highly strained nature of cyclopropanes possessing three vicinal quaternary carbon stereocenters.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Organic
Sheng Cao, Chen Li, Xuan Wang, Yilei Huang, Guang Yang, Yunhao Luo, Shuanglin Qin
Summary: A robust Pd(0)-catalyzed decarboxylation alkylation has been developed using chiral tert -butanesulfinamide as the directing group, allowing for the construction of quaternary chiral centers with high diastereoselectivities and high yields at the alpha-position of chiral sulfinamides.
Article
Chemistry, Multidisciplinary
Ke Li, Linsheng Wei, Minghe Sun, Bing Li, Min Liu, Changkun Li
Summary: A Co-catalyzed enantioselective desymmetric [2+2+2] cycloaddition has been developed for the synthesis of pyridines with all-carbon quaternary carbon centers, with regio- and enantioselectivities controlled by the nature of terminal alkynes and substituents on the bisoxazolinephosphine ligands. Pyridines with 5-substituents can be obtained with high regioselectivity and up to 94% ee, while pyridines with 6-substituents can be formed with up to 99% ee using different alkynes and ligands.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Joe Higham, James A. Bull
Summary: Transient directing groups (TDGs) combined with copper have been used for efficient C-H functionalization without additional steps for directing group introduction and removal. This method demonstrates high regioselectivity in the beta-C(sp(2))-H sulfonylation and gamma-(peri)-sulfonylation reactions of benzaldehydes and achieves through the use of catalytic beta-alanine and sulfinate salts, with copper fluoride serving as both the copper source and oxidant.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Review
Chemistry, Organic
Jiao-li Ma, Xu-ming Zhou, Jia-lin Chen, Jie-xin Shi, Hui-cheng Cheng, Peng-hu Guo, Hong-bing Ji
Summary: Construction of a carbon-nitrogen bond is a common operation in nature and organic synthesis. Rhodium-catalyzed C-H amination with directing-group strategies improves the step economy and atom economy of the reaction, complying with green chemistry principles. The reactivity and selectivity of chelation-assisted rhodium-catalyzed C-H amination are discussed, along with the challenges and future prospects in this field.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Sijing Xue, Alexander Lucht, Jordi Benet-Buchholz, Arjan W. Kleij
Summary: The challenging metal-catalyzed asymmetric synthesis of highly functional quaternary carbon centers using decarboxylative C(sp(3))-C(sp(3)) bond formation reactions has been successfully reported in this study. By activating a key substrate, a vinyl cyclic carbonate, both the requisite nucleophile and electrophile reaction partner were provided for the asymmetric cross-coupling process. Through extensive screening of reaction conditions, additives and catalyst precursors, a protocol was developed that allowed access to a series of compounds featuring densely functionalized, elusive quaternary carbon stereocenters in appreciable yield and with enantiomeric ratios (er's) of up to 90 : 10.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Multidisciplinary
Xinlong Yan, Zongwei Li, Lin Fan, Jiashan Li, Guodu Liu
Summary: In recent years, new methods for the preparation of chiral alkyl fluorides have been intensively studied due to their favorable physicochemical and biological properties. In this study, the regio- and enantio-selective allylic alkylation of alpha-pyridyl-alpha-fluoroesters with allyl acetates, promoted by Cu/Pd synergistic catalysis, was described, leading to the construction of carbon-fluorine quaternary stereocenters. The palladium catalyst primarily formed the C-C bond, while the chiral copper catalyst controlled the enantioselectivity. The reaction showed high yield, excellent enantioselectivity, and E/Z selectivity (up to 98% yield, 98:2 er, E/Z>20:1) with a series of aryl- and aliphatic-substituted allyl acetates.
CHEMISTRY-AN ASIAN JOURNAL
(2023)
Article
Chemistry, Physical
Xueling Mo, Han Huang, Guozhu Zhang
Summary: Synthesis of chiral tetrasubstituted carbon stereocenters is a challenging task in organic chemistry. This study demonstrates that asymmetric alkynylation using catalytic reactions can efficiently produce tertiary stereocenters and all-carbon quaternary stereocenters with synthetic and medicinal value.
Article
Chemistry, Multidisciplinary
Mikel Oiarbide, Claudio Palomo
Summary: Chiral Bronsted base (BB) catalyzed asymmetric transformations are important for synthesis. These transformations involve transiently generated enolate intermediates that react with a variety of electrophiles. Our group focused on developing BB-catalyzed asymmetric reactions of enolizable carbonyl substrates, with an additional challenge of controlling site-selectivity. This account illustrates the opportunities and challenges of these methods, with a focus on generating quaternary carbon stereocenters. New bifunctional BB catalysts and achiral templates were developed during this process.
Article
Chemistry, Organic
Rekha Thakur, Iqubal Singh, Kamaldeep Paul
Summary: In this study, direct C-H alkenylation of 1,8-naphthalimide using cyclic imide as a weak directing group and ruthenium catalyst was explored. The alkenyl group(s) were successfully introduced into the 1,8-naphthalimide skeleton at the inactive C2 and/or C7 positions. The aromatic ring of 1,8-naphthalimide was substituted with electron-withdrawing and electron-donating groups, and N-alkyl/aryl groups on cyclic imide were found compatible in these coupling reactions.
ASIAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Monika Pareek, Raghavan B. Sunoj
Summary: The study investigates the nature of potential active catalyst, energetic features of the catalytic cycle, and the origin of high enantioselectivity in the asymmetric allylic alkylation reaction of alpha,alpha-disubstituted aldehydes. It is found that the in-situ formation of a Rh-phosphonate likely acts as an active catalyst, leading to the formation of a quaternary stereogenic center. The stereochemical preference for the formation of product on the re face is attributed to improved noncovalent interactions and less distortion in the enantiocontrolling C-C bond formation transition state. The computed enantioselectivity and activation barrier are in good agreement with experimental values.
Article
Chemistry, Applied
Xiaoting Gu, Xiaoxiang Zhang, Wenhua Yu, Ke Sun, Wanxing Wei, Zhuan Zhang, Taoyuan Liang
Summary: This study presents a directing-group-free, three-component tandem C3-acylation/C5,6-H disulfenylation method for the position-selective functionalization of the poorly reactive benzenoid nucleus of indoles. The protocol demonstrates exceptional regio- and chemo-selectivity, broad substrate scope, good functional group tolerance, and mild reaction conditions. Importantly, this method offers great potential for the development of general site-selective functionalization at the benzenoid nucleus of indoles without the requirement for neighboring activating groups.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Chemistry, Multidisciplinary
Dunqi Wu, Lianqian Wu, Pinhong Chen, Guosheng Liu
Summary: Alkynes play important roles in natural products and organic synthesis, but the enantioselective construction of alkyne substituted all carbon quaternary stereocenters has been a challenging task in asymmetric radical reactions. In this study, we discovered that introducing an amidyl group next to the tertiary carbon radical enables the asymmetric radical coupling with alkyne reagents, providing a straightforward and efficient access to chiral quaternary all-carbon centers bearing alkynyl groups.
CHINESE JOURNAL OF CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Juanjuan Wu, Hongli Wu, Xinzhi Li, Xinyu Liu, Qian Zhao, Genping Huang, Chun Zhang
Summary: The study presents a copper-catalyzed highly selective protoboration reaction that can suppress defluorination and provide CF3-containing borated reagents. Functional group tolerance of this reaction is well demonstrated, with the products serving as versatile precursors for various transformations. By using a chiral diphosphine ligand, allylic boron reagents with a CF3-containing chiral center were synthesized for the first time. Additionally, in-depth DFT calculations were conducted to understand the mechanism behind the inhibition of defluorination.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Guolin Wu, Yuan Yao, Gen Li, Xue Zhang, Hui Qian, Shengming Ma
Summary: This study developed a catalytic recipe of copper halides to address the issues of side reactions and selectivity in the 1,5-H transfer of alka-1,4-diyn-3-yl amines, providing various allenynes with excellent enantioselectivities. The method was successfully applied to the first highly enantioselective total synthesis of the natural product scorodonin. Mechanistic studies and DFT calculations elucidated the regioselectivity for the observed 1,5-H transfer.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
