- CuI–Zn(OAc)2 catalyzed C(sp2)–H activation for the synthesis of pyridocoumarins through an uncommon CuI–CuIII switching mechanism: A fast, solvent-free, combo-catalytic, ball milling approach
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CuI–Zn(OAc)2 catalyzed, a fast, solvent-free synthetic protocol has been developed for the oxidative C–C and C–N coupling via C(sp2)–H activation. In this work, an aldehyde, terminal alkyne and 3-aminocoumarin were coupled together to form pyridocoumarin framework through a greener ball milling process under very mild condition. In contrast to the frequently used imine-alkyne cyclization reactions, this uncommon mild CuI–CuIII switching combo-catalysis is expected to proceed through the formation of a flexible propargylic amine intermediate, which leads to a rapid C(sp2)–H activation for cyclization involving transient CuIII species. The in-situ formation of transient CuIII species was confirmed through ultraviolet–visible spectroscopy (UV–Vis), electrospray ionization mass spectrometry (ESI-MS), and X-ray photoelectron spectroscopy (XPS) analyses of the reaction mixture.
- Kausar, Nazia,Das, Asish R.
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supporting information
p. 2602 - 2607
(2017/06/13)
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- Efficient Synthesis of Functionalized Pyrido[2,3- c ]coumarin Derivatives by a One-Pot Three-Component Reaction
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A methanesulfonic acid promoted three-component reaction has been developed for the synthesis of functionalized pyrido[2,3-c]coumarin derivatives from ketones, aromatic aldehydes, and 3-aminocoumarin. In this simple and efficient protocol, products were obtained in moderate to good yields (28 examples). The reaction proceeds by an asynchronous [4+2] cycloaddition (inverse-electron-demand Diels-Alder reaction).
- Chen, Zhiwei,Hu, Lele,Peng, Fei
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p. 1888 - 1892
(2016/07/16)
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- A simple and expedient synthesis of functionalized pyrido[2,3-c] coumarin derivatives using molecular iodine catalyzed three-component reaction
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A wide variety of substituted pyrido[2,3-c] coumarin derivatives have been accomplished from 3-aminocoumarins, aromatic aldehydes, and alkynes in the presence of 10 mol % molecular iodine in acetonitrile under reflux conditions through one-pot Povarov reactions. Good yields, no need of aqueous work-up procedure and chromatographic separation, environmentally benign are some of the salient features of the present protocol.
- Khan, Abu T.,Das, Deb K.,Islam, Kobirul,Das, Pradipta
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p. 6418 - 6422,5
(2012/12/12)
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- A simple and expedient synthesis of functionalized pyrido[2,3-c] coumarin derivatives using molecular iodine catalyzed three-component reaction
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A wide variety of substituted pyrido[2,3-c] coumarin derivatives have been accomplished from 3-aminocoumarins, aromatic aldehydes, and alkynes in the presence of 10 mol % molecular iodine in acetonitrile under reflux conditions through one-pot Povarov reactions. Good yields, no need of aqueous work-up procedure and chromatographic separation, environmentally benign are some of the salient features of the present protocol.
- Khan, Abu T.,Das, Deb K.,Islam, Kobirul,Das, Pradipta
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p. 6418 - 6422
(2013/01/15)
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