Studies of bioactive heterocycles: facile thio-Claisen rearrangement of propargylthio[1]benzopyran-2-ones
作者:K.C Majumdar、S.K Ghosh
DOI:10.1016/s0040-4039(02)00195-8
日期:2002.3
Hitherto unreported 2H-thiopyrano[3,2-c][1]benzopyran-5-ones 6a–f are synthesized regioselectively in 79–85% yields by the thio-Claisen rearrangement of 4-propargylthio[1]benzopyran-2-ones 5a–f. The substrates 5a–f are synthesized by alkylation of hitherto unreported 4-mercaptocoumarins.
N-Heterocyclic Carbene Derived Nickel-Pincer Complexes: Efficient and Applicable Catalysts for Suzuki-Miyaura Coupling Reactions of Aryl/Alkenyl Tosylates and Mesylates
作者:Jun-ichi Kuroda、Kiyofumi Inamoto、Kou Hiroya、Takayuki Doi
DOI:10.1002/ejoc.200900067
日期:2009.5
activities of NHC-derived nickel–pincercomplexes for the Suzuki–Miyauracouplingreactions of aryl/alkenyltosylates and mesylates are described. In the presence of a catalytic amount of nickelacycle 1a, a wide array of tosylates and mesylates reacted with several aryl- and alkenylboronic acids to afford the coupling products, generally in high yields. Fine tuning of the reaction conditions for each class
4-thio substituted coumarin derivatives and coumarin dimers are provided, as well as processes for their preparation. A synthetic process for the preparation of 4-thio substituted coumarin derivatives is provided using mild reaction conditions, which maintains a high substituent tolerance and is appropriate for use in solid phase syntheses for producing a library of 4-thio substituted coumarin derivatives for biological screening.
Palladium-catalyzed Suzuki–Miyaura couplings of potassium aryl trifluoroborates with 4-tosyloxycoumarins or 4-tosyloxyquinolin-2(1H)-one
作者:Jie Wu、Liang Zhang、Hong-Guang Xia
DOI:10.1016/j.tetlet.2006.01.020
日期:2006.3
Pd(PPh3)4catalyzed Suzuki–Miyaura cross-coupling reactions of 4-tosyloxycoumarins or 4-tosyloxyquinolin-2(1H)-one with various potassium aryl trifluoroborates afforded the corresponding 4-substituted coumarins or 4-substituted quinolin-2(1H)-ones in good to excellent yield.
Facile synthesis of 4-acetyl-coumarins, -thiocoumarin and -quinolin-2(1H)-one via very high α-regioselective Heck coupling on tosylates
作者:Sergio Valente、Gilbert Kirsch
DOI:10.1016/j.tetlet.2011.04.033
日期:2011.7
An efficient synthesis of a series of methyl ketones at the C4 position of coumarins, coumarin-containing heterocycles and analogous scaffolds is reported via very high α-regioselective Heck coupling using tosylates and in very high yields. Although α-regioselectivity in Heck coupling can be obtained with triflates as substrates, tosylates are less toxic, less expensive and, importantly, more stable