Article
Chemistry, Organic
Estelle Silm, Ivar Jarving, Tonis Kanger
Summary: An asymmetric Michael reaction between cyclopentane-1,2-dione and alkylidene oxindole was studied using a multifunctional squaramide catalyst, resulting in high enantioselectivities and moderate diastereoselectivities of the Michael adducts.
BEILSTEIN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Suna Han, Xin Shen, Xiaoxue Wu, Chaochao Xie, Guofu Zi, Guohua Hou
Summary: In this study, a Cu-catalyzed highly diastereo- and enantioselective methylboration reaction of diverse heterocyclic compounds was realized for the first time. The reaction provides the corresponding organoboron compounds bearing two adjacent chiral centers with excellent diastereoselectivities and enantioselectivities. This method offers an efficient and highly enantioselective approach for the synthesis of chiral organoboron compounds and their derivatives containing heterocyclic structures.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Organic
Mengzhu Guo, Fengying Dong, Xiangcong Yin, Lubin Xu, Liang Wang, Shuai-Shuai Li
Summary: In this study, medicinally significant 3-monosubstituted tetrahydroquinolines and 1,2-dihydroquinolines were controllably constructed via a redox-neutral vinylogous cascade condensation/[1,5]-hydride transfer/cyclization process in ethanol, showcasing novel features such as green solvent and metal-free conditions. Additionally, the electrophilicity and nucleophilicity of alpha,alpha-dicyanoalkenes were effectively utilized as hydride acceptors and gamma-exclusive nucleophiles.
ORGANIC CHEMISTRY FRONTIERS
(2021)
Article
Chemistry, Organic
Sumi Joseph, Qui-Nhi Duong, Lukas Schifferer, Olga Garcia Manchen
Summary: An enantioselective anion-binding catalyzed allylation method has been developed for the rapid synthesis of chiral α-allyl dihydroquinolines. Using a tetrakis-triazole-based hydrogen-bond donor catalyst, these chiral N-heterocycles were obtained in good yields (up to 90%) and with high enantioselectivity (up to 89:11 e. r.). Moreover, the versatility of the allyl moiety in the products was demonstrated through selective post-epoxidation and aziridination reactions, resulting in highly decorated chiral molecules with up to four stereocenters and high enantioselectivity (up to 94:6 e. r.).
Article
Chemistry, Organic
Dmitri Trubitson, Jevgenija Martonova, Marina Kudrjasova, Kristin Erkman, Ivar Jarving, Tonis Kanger
Summary: An efficient enantioselective organocatalytic method has been developed for the synthesis of N-alkylated indoles with alpha-branched alkyl substituents from unsaturated indolyl ketones via a Michael addition. The resulting products exhibit high enantioselectivities and good yields, with tolerance towards various nucleophiles and substitution patterns of the indole ring. Both electron-withdrawing and electron-donating substituents can be accommodated at any position of the heteroaromatic ring.
Article
Chemistry, Organic
Chandan Gharui, Chandrakanta Parida, Subhas Chandra Pan
Summary: An organocatalytic asymmetric addition reaction of aromatic alpha-cyanoketones to in situ-generated o-quinone methides was successfully developed, leading to the synthesis of 3,4-dihydrocoumarin and tetrasubstituted chroman products. The desired products were obtained with high enantio- and diastereoselectivities under 10 mol % catalyst.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Biochemistry & Molecular Biology
Hongwen Mu, Yan Jin, Rongrong Zhao, Liming Wang, Ying Jin
Summary: In this study, bifunctional Takemoto's catalysts were used to catalyze the enantioselective Michael reaction of aminomaleimides with nitroolefins. The resulting products showed good yields and high enantiomeric excess.
Article
Chemistry, Applied
Fushuai Li, Zhihong Yang, Yanyan Yang, Qiuhong Huang, Xuling Chen, Pengfei Li, Mingxin Dong, Wenjun Li
Summary: A chiral phosphorus acid catalyzed enantioselective 1,4-conjugate addition of arylamines to in situ formed 7-methylene-7H-indoles from 7-indolylmethanols has been successfully developed for the first time without the use of additives. The catalytic protocol enables the formation of 1,4-adducts with a nitrogen-containing tertiary carbon stereocenter in moderate to high yields and good enantioselectivity under mild reaction conditions.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Applied
Laura A. Bryant, Kenneth Shankland, Hannah E. Straker, Callum D. Johnston, Nicholas R. Lees, Alexander J. A. Cobb
Summary: The article describes a rare organocatalytic intramolecular cyclization of resorcinols with a high enantioselectivity using a specific organocatalyst. The obtained bicyclic resorcinols show excellent utility in the synthesis of cannabinoid-like compounds, and exhibit anticonvulsant activity.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Multidisciplinary
Jingwen Wei, Yangyang Xing, Xiaohan Ye, Bao Nguyen, Lukasz Wojtas, Xin Hong, Xiaodong Shi
Summary: In this study, a new synthetic strategy for enantioselective 1,2-dihydropyridine synthesis was reported. Using the gold-catalyzed intermolecular condensation of amine and diyne-ene, the synthesis was achieved through a formal [3+2+1] fashion with up to 95% yield and up to 99% enantiomeric excess (e.e.).
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Organic
Shi-Jie Zhu, Zhi-Feng Hao, Ya Pan, Ying Zhou, Xiong-Li Liu, Ming Zhang, Chuan-Wen Lei
Summary: In this study, a stepwise enantioselective formal (3 + 2) cyclocondensation reaction was successfully accomplished, leading to the synthesis of spiro-fused pentacyclic spirooxindoles. The reaction showed good overall yields, excellent dr, and high ee values.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Shi-Jie Zhu, Zhi-Feng Hao, Ya Pan, Ying Zhou, Xiong-Li Liu, Ming Zhang, Chuan-Wen Lei
Summary: The first enantioselective formal (3 + 2) cyclocondensation involving alpha,fi-unsaturated pyrazoleamides as 3-carbon partners was successfully achieved in a stepwise fashion. The protocol led to the synthesis of spiro-fused pentacyclic spirooxindoles with good overall yields, excellent diastereomeric ratios, and high enantiomeric excess values.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Chandrakanta Parida, Buddhadeb Mondal, Animesh Ghosh, Subhas Chandra Pan
Summary: A novel organocatalytic asymmetric synthesis method for spirooxindole embedded oxazolidines has been developed using a specific catalyst, resulting in good diastereoselectivity and high enantioselectivity of the products.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Qingfa Tan, Ning Guo, Linhan Yang, Fei Wang, Xiaoming Feng, Xiaohua Liu
Summary: Pudovik addition/[1,2]-phospha-Brook rearrangement is an effective method for generating anionic nucleophiles and constructing C-C bonds in organic synthesis. In this study, we report the organocatalytic 1,6-conjugate addition of para-quinone methides using Pudovik addition/[1,2]-phospha-Brook rearrangement. The three-component reaction, catalyzed by a chiral guanidine-sulfonamide, showed high yields and excellent diastereo- and enantioselectivities, leading to biologically active oxindole/biaryl/phosphorus-based structures. A possible bifunctional catalytic mode was proposed to explain the chiral control of this process.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Ruslan A. Kovalevsky, Maxim Smirnov, Alexander S. Kucherenko, Kseniya A. Bykova, Elizaveta Shikina, Sergei G. Zlotin
Summary: In this study, 2-nitroallylic carbonates were used for the first time as promising biselectrophilic C3 synthons. They reacted with kojic acid derivatives in a bifunctional squaramide catalyzed asymmetric domino reaction, yielding nitro compounds that contain two hydroxypyranone units. The reaction products undergo noncatalytic epimerization at the carbon atom next to the nitro group. A plausible mechanism of the epimerization based on reversible formation of intermediate aci-nitro compound is proposed. The double addition products were transformed into configurationally stable acetates and chiral nitro glutarates, which are promising precursors for chiral amino glutaric acid derivatives.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
