We disclose a Ag-catalyzed asymmetric interrupted Barton-Zard reaction of α-aryl-substituted isocyanoacetates with 2- and 3-nitroindoles, which enables the dearomatization of nitroindoles and hence offers rapid access to an array of optically active tetrahydropyrrolo[3,4-]indole derivatives bearing three contiguous stereogenic centers, including two tetrasubstituted chiral carbon atoms with pretty outcomes (up to 99% yield, 91:9 dr, and 96% ee). The synthetic potential of the protocol was showcased by the gram-scale reaction and versatile transformations of the product.
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http://dx.doi.org/10.1021/acs.orglett.1c04036 | DOI Listing |
Chemistry
November 2024
Department, of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki Aza Aoba, Aoba-ku, Sendai, 980-8578, Japan.
N-Sulfinylimines derived from ortho-alkynylbenzaldehydes were efficiently converted into the corresponding 4-sulfinylisoquinolines in good to excellent yields. The reaction proceeds via cyclization followed by intermolecular migration of the sulfinyl group from the nitrogen atom to the silver-bound carbon of the resulting cyclized vinylsilver intermediate with the aid of either a counteranion or a nucleophilic species. Moreover, the Ag-catalyzed reaction in the presence of quinidine acetate as a chiral nucleophilic cocatalyst yielded chiral isoquinolines with high enantioselectivities through a dynamic kinetic asymmetric transformation (DYKAT).
View Article and Find Full Text PDFJ Org Chem
December 2024
Molecular Synthesis Center & Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao 266003, China.
A Ag-catalyzed [2 + 3] cycloaddition of alkylidene azlactones with trifluoromethylated imines has been documented, providing spiro[pyrrolidine-azlactones] bearing four adjacent stereogenic centers with good yields and excellent diastereoselectivities. Catalytic asymmetric cycloaddition has also been developed with good yields and excellent enantioselectivities. Further gram-scale preparation and synthetic transformation to pyrrolidine derivative showed the good practicality and applicability of this reaction.
View Article and Find Full Text PDFOrg Lett
March 2024
Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan.
Because scaffold diversity has a pronounced impact on biological screening, the efficient and expedient construction of skeletally diverse compound collections is a fundamental demand in drug discovery. In this regard, we report here an asymmetric tandem conjugate addition-elimination reaction of pyrroline esters with nitroallyl acetates and its application to the construction of various types of fused or spirocyclic pyrrolidines. A AgOAc/(,)-ThioClickFerrophos (TCF) catalyst efficiently promotes the addition-elimination reaction, setting vicinal chiral stereocenters featuring a tetrasubstituted carbon with excellent enantio- and diastereoselectivity while leaving the versatile nitroolefin moiety.
View Article and Find Full Text PDFAcc Chem Res
September 2022
Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education and Key Laboratory of Organosilicon Material Technology of Zhejiang Province, College of Materials, Chemistry and Chemical Engineering, Hangzhou Normal University, No. 2318, Yuhangtang Road, Hangzhou 311121, P. R. China.
Enantiopure atropisomers have become increasingly important in asymmetric synthesis and catalysis, pharmaceutical science, and material science since the discovery of inherent features of axial chirality originating from rotational restriction. Despite the advances made in this field to date, it remains highly desirable to construct structurally diverse atropisomers with potentially useful functions. We propose superposition to match axial and point chirality as a potentially useful strategy to access structurally complex and diverse building blocks for organic synthesis and pharmaceutical science because merging atropisomeric backbones with one or more extra chiral elements can topologically broaden three-dimensional environments to create complex scaffolds with multiple tunable parameters.
View Article and Find Full Text PDFChem Asian J
August 2022
Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga Bunkyo-ku, 112-8551, Tokyo, Japan.
An unprecedented Ag-catalyzed exo'-selective [3+2] cycloaddition of imino esters with 4-benzylidene-2,3-dioxopyrrolidines is described. The reaction was efficiently catalyzed by Ag/(R, S )-ThioClickFerrophos (TCF) leading to the construction of the corresponding spirobipyrrolidine scaffolds in excellent enantio- and diastereoselectivities. This reaction is the first example of a silver-catalyzed exo'-selective asymmetric [3+2] cycloaddition, as well as the first exo'-selective spirobipyrrolidine construction via a [3+2] cycloaddition process using imino esters.
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