A photoredox one-pot strategy for efficient accessing 3,4-dihydroquinolin-2(1H)-ones from anilines, oxalyl chloride, and electron-deficient alkenes is disclosed. The new approach features excellent synthetic efficiency, readily available starting materials, and simple operations. It is compatible with a variety of anilines and electron-deficient alkenes. A broad array of 3,4-dihydroquinolin-2(1H)-ones were prepared.
This paper describes the total syntheses of spirooliganones A and B, which provides control over the stereochemistry of the spiro center via a cascade reaction involving the in situ formation of an o-quinone methide and a hetero-Diels–Alder reaction.
An Ir/Ag dual-catalysis method has been developed for the synthesis of β-anti-substituted α-amino acids in high yields and with good enantioselectivities through a ligand/chelation-control strategy. By using this chiral-ligand-control strategy, a natural product for the regulation of a plant-growth hormone was synthesized on a gram scale in three steps.
Optically active amines represent critically important subunits in bioactive natural products and pharmaceuticals, as well as key scaffolds in chiral catalysts and ligands. Kinetic resolution of racemic amines and enantioselective desymmetrization of prochiral amines have proved to be efficient methods to access enantioenriched amines, especially when the racemic or prochiral amines were easy to prepare while the chiral ones are difficult to be accessed directly. In this Account, we systematically summarized the development of kinetic resolution and desymmetrization of amines through nonenzymatic asymmetric catalytic approaches in the last two decades.1 Introduction2 Kinetic Resolution of Amines2.1 Kinetic Resolution of Amines via Asymmetric Transformations of the Amino Group2.1.1 Asymmetric N-Acylations2.1.2 Asymmetric N-Alkylation2.1.3 Asymmetric N-Arylation2.1.4 Other Asymmetric N-Functionalizations2.1.5 Asymmetric Dehydrogenation of Amines2.1.6 Selective C–N Bond Cleavage of Amines2.2 Kinetic Resolution of Amines via Asymmetric Transformations without Amino Group Participating3 Enantioselective Desymmetrization of Amines3.1 Desymmetrization of Diamines3.2 Desymmetrization of Prochiral Monoamines4 Conclusion and Outlooks
Modifications of glycosidic linkers are valuable in medicinal chemistry and natural-product synthesis. Whereas considerable attention has been paid to the development of methods for monoglycosylation, the corresponding geminal diglycosylation has almost been ignored. Little work has focused on exploring new routes for stereoselective gem-diglycosylation, presumably due to challenges in controlling selectivity and activity on a confined quaternary carbon center. Highlighted herein is a recent advance in stereoselective C,B-glycosylation through an unprecedented PPh3-promoted 1,2-boronate-migration process.
We recently discovered a functional group tolerant and transition-metal-free conjunctive olefination reaction with applications in late-stage functionalization chemistry. In this Synpacts contribution, we analyze the conceptual background that has stimulated the discovery of this reactivity and reflect on the key aspects of its development.1 Introduction2 Conceptual Background2.1 Photoredox-Mediated Giese Reaction2.2 Photoredox Radical-Polar Reactivity3 The Development of the Process4 Conclusion
Synlett 2022; 33: 502-502DOI: 10.1055/s-0041-1737398Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals:Table of contents | Full text
Synlett 2022; 33: V-DOI: 10.1055/s-0041-1737399Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals:Table of contents
This account highlights the role of restricted bond rotations in influencing the excited-state reactivity of organic molecules. It highlights the photochemical reactivity of various organic molecules and the design strategies that could be exploited by chemists to utilize restricted bond rotations to uncover new excited-state reactivity and to achieve selectivity.1 Introduction.2 NEER-Principle and Restricted Bond Rotations in the Excited State3 [2+2]-Photocycloaddition of Enamides4 [3+2]-Photocycloaddition vs. Paternò–Büchi Reaction of Enamides5 Divergent Photoreactivity of Enones Dictated by Restricted Bond Rotations: Norrish–Yang reactions vs. 6π-Photocyclization6 Divergent Photoreactivity of Imides with Alkenes: [2+2]-Photocycloaddition vs. Photoene Reaction7 Summary and Outlook
Three different heterocyclic systems (3-amidocoumarins, 3-amidoazacoumarins, and N-benzoylindol-2-carboxamides) were synthesized based on the strikingly different selectivity of copper-mediated C–O/C–N bond formation from azlactones under various heating conditions. The stereochemistry of the double bond dictated the nature of the products. Microwave irradiation played an important role in the isomerization of the trisubstituted olefin leading to the formation of 3-amidocoumarins and 3-amidoazacoumarins. Three products showed promising-to-good cytotoxic activities against a panel of cancer cell lines, including HepG2 (hepatoblastoma) and MOLT-3 (T-lymphoblast acute lymphoblastic leukemia).