607-71-6Relevant articles and documents
A tandem palladium-catalyzed Heck-lactonization through the reaction of ortho-iodophenols with β-substituted acrylates: synthesis of 4,6-substituted coumarins
Fernandes, Talita de A.,Carvalho, Rita de C.C.,Gon?alves, Tatiana M.D.,da Silva, Alcides J.M.,Costa, Paulo R.R.
, p. 3322 - 3325 (2008)
Coumarins were obtained in one pot through a palladium-catalyzed Heck-lactonization reaction involving ortho-iodophenols and methyl crotonate or a Z-enoate derived from d-mannitol. These reactions were investigated under different conditions and palladium sources. In the more interesting cases, coumarins were prepared in water, using triethylamine as base and 1 mol % of PdCl2 as catalyst.
Iridium-catalyzed enantioselective direct vinylogous allylic alkylation of coumarins
Sarkar, Rahul,Mitra, Sankash,Mukherjee, Santanu
, p. 5767 - 5772 (2018)
The first iridium-catalyzed enantioselective vinylogous allylic alkylation of coumarins is presented. Using easily accessible linear allylic carbonates as the allylic electrophile, this reaction installs unfunctionalized allyl groups at the γ-position of
Shape-, size-, and functional group-selective binding of small organic guests in a paramagnetic coordination cage
Turega, Simon,Whitehead, Martina,Hall, Benjamin R.,Meijer, Anthony J. H. M.,Hunter, Christopher A.,Ward, Michael D.
, p. 1122 - 1132 (2013)
The host-guest chemistry of the octanuclear cubic coordination cage [Co8L12]16+ (where L is a bridging ligand containing two chelating pyrazolyl-pyridine units connected to a central naphthalene-1,5-diyl spacer via methylene "hinges") has been investigated in detail by 1H NMR spectroscopy. The cage encloses a cavity of volume of ca. 400 A3, which is accessible through 4 A diameter portals in the centers of the cube faces. The paramagnetism of the cage eliminates overlap of NMR signals by dispersing them over a range of ca. 200 ppm, making changes of specific signals easy to observe, and also results in large complexation-induced shifts of bound guests. The cage, in CD3CN solution, acts as a remarkably size-and shape-selective host for small organic guests such as coumarin (K = 78 M-1) and other bicyclic molecules of comparable size and shape such as isoquinoline-N-oxide (K = 2100 M-1). Binding arises from two independent recognition elements, which have been separately quantified. These are (i) a polar component arising from interaction of the H-bond accepting O atom of the guest with a convergent group of CH protons inside the cavity that lie close to a fac tris-chelate metal center and are therefore in a region of high electrostatic potential; and (ii) an additional component arising from the second aromatic ring (aromatic/van der Waals interactions with the interior surface of the cage and/or solvophobic interactions). The strength of the first component varies linearly with the H-bond-accepting ability of the guest; the second component is fixed at approximately 10 kJ mol-1. We have also used 1H-1H exchange spectroscopy (EXSY) experiments to analyze semiquantitatively two distinct dynamic processes, viz. movement of the guest into and out of the cavity and tumbling of the guest inside the host cavity. Depending on the size of the guest and the position of substituents, the rates of these processes can vary substantially, and the rates of processes that afford observable cross-peaks in EXSY spectra (e.g., between free and bound guest in some cases; between different conformers of a specific host·guest complex in others) can be narrowed down to a specific time window. Overall, the paramagnetism of the host cage has allowed an exceptionally detailed analysis of the kinetics and thermodynamics of its host-guest behavior.
B(C6F5)3-catalyzed synthesis of coumarins via Pechmann condensation under solvent-free conditions
Prajapti, Santosh Kumar,Rao, S. Prakash
, p. 469 - 473 (2021/03/26)
Tris(pentafluorophenyl)borane [B(C6F5)3] catalyzed simple, efficient and environmentally benign protocol has been developed for the Pechmann condensation using variety of phenols and β-ketoesters under solvent-free conditions to afford coumarin derivatives. The present protocol displayed significant advantages such as low catalyst loading, short reaction time, mild reaction conditions, low toxicity, easy work-up, high yields, and compatibility with other functional groups. In addition, it is a convenient, clean, and fast alternative approach for synthesizing variety of coumarin derivatives. Moreover, the applicability of this method towards large-scale synthesis demonstrated its suitability for the industrial application. Graphic abstract: [Figure not available: see fulltext.]
Nickel-Catalyzed Hydrodeoxygenation of Aryl Sulfamates with Alcohols as Mild Reducing Agents
Matsuo, Kasumi,Kuriyama, Masami,Yamamoto, Kosuke,Demizu, Yosuke,Nishida, Koyo,Onomura, Osamu
, p. 4449 - 4460 (2021/08/25)
The nickel-catalyzed hydrodeoxygenation of aryl sulfamates has been developed with alcohols as mild reductants. A variety of functional groups and heterocycles were tolerated in this reaction system to give the desired products in high yields. In addition, the gram-scale process and stepwise cine-substitution were also achieved with high efficiency.
Visible-light promoted oxidative cyclization of cinnamic acid derivatives using xanthone as the photocatalyst
Zhao, Bin,Xu, Bo
supporting information, p. 568 - 573 (2021/02/06)
We have developed an efficient photocatalytic synthesis of coumarin derivativesviaa tandem double bond isomerization/oxidative cyclization of cinnamic acids. Inexpensive and stable xanthone was used as the photocatalyst, and readily available Selectfluor was used as the oxidant. This method tolerates a wide range of functional groups and offers excellent chemical yields in general. Besides, the photocatalytic oxidative cyclization of cinnamic acid esters gives dimerized lignan-type products.
