Org Lett
Department of Chemistry, University of South Florida, 4202 East Fowler Avenue, CHE205A, Tampa, FL 33620, USA.
Published: July 2007
The highly enantioselective organocatalytic addition of N-benzyl indoles to N-acyl imines is reported. A total of 15 examples with product yield ranging from 89% to 99% and enantioselectivities from 90% to 97% are presented. A chiral phosphoric acid catalyst derived from a hindered binol derivative was employed most effectively in the reaction. Attractive features of the reaction include desirable catalyst loadings, good reactivity, generality of substrates, and easily removable groups from both nitrogen atoms.
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http://dx.doi.org/10.1021/ol0703579 | DOI Listing |
Chemistry
January 2025
Beijing Normal University, College of Chemistry, Xiejiekou NO.19, 100875, Beijing, CHINA.
Optically pure monosubstituted [n]paracyclophanes are promising candidates for material synthesis, asymmetric catalysis, and drug discovery. Thus far, only a few catalytic asymmetric synthesis processes have been reported for assessing these stained atropisomers. In this study, we describe a highly enantioselective synthesis of monosubstituted [n]paracyclophanes by combining desymmetrization and kinetic resolution.
View Article and Find Full Text PDFChem Sci
December 2024
Department of Chemistry, Biology and Biotechnology, University of Perugia Via Elce di Sotto, 8 06123 Perugia Italy
The majority of enantioselective organocatalytic reactions occur in apolar or weakly polar organic solvents. Nevertheless, the influence of solute-solvent van der Waals forces on the relative kinetics of competitive pathways remains poorly understood. In this study, we provide a first insight into the nature and strength of these interactions at the transition state level using advanced computational tools, shedding light into their influence on the selectivity.
View Article and Find Full Text PDFElectrophoresis
January 2025
Institute for Infectious Diseases, University of Bern, Bern, Switzerland.
Computer simulation was utilized to characterize the electrophoretic processes occurring during the enantioselective capillary electrophoresis-mass spectrometry (CE-MS) analysis of ketamine, norketamine, and hydroxynorketamine in a system with partial filling of the capillary with 19 mM (equals 5%) of highly sulfated γ-cyclodextrin (HS-γ-CD) and analyte detection on the cathodic side. Provided that the sample is applied without or with a small amount of the chiral selector, analytes become quickly focused and separated in the thereby formed HS-γ-CD gradient at the cathodic end of the sample compartment. This gradient broadens with time, remains stationary, and gradually reduces its span from the lower side due to diffusion such that analytes with high affinity to the anionic selector become released onto the other side of the focusing gradient where anionic migration and defocusing occur concomitantly.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Organic Chemistry, Indian Institute of Science, Bangalore 560012, India.
Despite tremendous progress of dienamine catalysis along with its application in enantioselective synthesis over nearly two decades, certain limitations, especially with respect to the regioselectivity in the dienamine generation step, continue to persist. To overcome these shortcomings of classical dienamine catalysis, we now introduce the concept of alkoxy-directed dienamine catalysis and apply it to the enantioselective arene construction by desymmetrizing -enediones through [4 + 2]-cycloaddition. Catalyzed by a diphenylprolinol silyl ether, this reaction utilizes γ-alkoxy α,β-unsaturated aldehydes as the substrate and proceeds in a highly regioselective fashion through the intermediacy of δ-alkoxy dienamine.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Zhejiang Uiversity, Chemistry, 866 Yuhangtang Road, 310058, Hangzhou, CHINA.
Heck silylation of unactivated alkenes is an efficient strategy for the synthesis of useful organosilicon compounds. However, extensive efforts have been dedicated to only achieving achiral molecules. Herein, a highly regio- and enantioselective cobalt-catalyzed Heck silylation of unactivated alkenes with hydrosilanes is reported for the first time, providing access to axially chiral alkenes in good to excellent yields with 87-98% ee.
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