Triple CH functionalization: Palladium‐catalyzed synthesis of benzofurans and coumarins by reacting phenols and unactivated olefins is described. The reaction comprises sequential CH functionalization and shows diverse functional group compatibility. Preliminary mechanistic studies shed light into the possible mechanisms.
A highly effective cascade process giving 3-alkenylcoumarins is furnished by a series of reactions involving pallada-arylation of ethylpropiolate with phenols, intramolecular transesterification t...
A novel, practical and metal-free approach for the regioselective selenation of coumarins employing (bis(trifluoroacetoxy)iodo)benzene (PIFA) at room temperature is presented. The developed method is suitable for a wide substrate scope and affords 3-selenyl coumarins in good to excellent yields with high selectivity. A radical mechanism is proposed for this new transformation. Furthermore, the application
Rh-Catalyzed Synthesis of Coumarin Derivatives from Phenolic Acetates and Acrylates <i>via</i> C–H Bond Activation
作者:Sunita K. Gadakh、Soumen Dey、Arumugam Sudalai
DOI:10.1021/acs.joc.5b01713
日期:2015.11.20
An efficient annulation strategy involving the reaction of phenolic acetates with acrylates in the presence of [Rh2(OAc)4] as catalyst and formic acid as reducing agent, leading to the high yield synthesis of coumarin derivatives, has been developed. The addition of NaOAc as a base increased the yield of the products. The reaction is quite successful for both electron-rich as well as electron-deficient
Synthesis of coumarins by Pt-catalyzed hydroarylation of propiolic acids with phenols
作者:Juzo Oyamada、Tsugio Kitamura
DOI:10.1016/j.tet.2006.04.080
日期:2006.7
Synthesis of coumarins from phenols and propiolicacids was examined by using a Pt catalyst such as PtCl2/AgOTf, K2PtCl4/AgOTf, and K2PtCl4/AgOAc. Propiolicacid reacted even with less reactive phenols in trifluoroacetic acid to give coumarins and dihydrocoumarins. In the case of substitutedpropiolicacids, phenylpropiolic acid and 2-octynoic acid, the reactions proceeded selectively to afford coumarins