57197-15-6Relevant articles and documents
A Stereoselective Arylative-Cyclopropanation Process
Coulibali, Siomenan,Deruer, Elsa,Godin, Elizabeth,Canesi, Sylvain
supporting information, p. 1188 - 1191 (2017/03/14)
A new stereoselective arylative cyclopropanation process involving treatment of halogenated dienone systems in the presence of a Michael donor containing a nitro-aryl-sulfone has been developed. This transformation enables production of an arylated cyclop
Br?nsted acid-controlled [3 + 2] coupling reaction of quinone monoacetals with alkene nucleophiles: A catalytic system of perfluorinated acids and hydrogen bond donor for the construction of benzofurans
Hu, Yinjun,Kamitanaka, Tohru,Mishima, Yusuke,Dohi, Toshifumi,Kita, Yasuyuki
, p. 5530 - 5543 (2013/07/26)
We have developed an efficient Br?nsted acid-controlled strategy for the [3 + 2] coupling reaction of quinone monoacetals (QMAs) with nucleophilic alkenes, which is triggered by the particular use of a specific acid promoter, perfluorinated acid, and a solvent, fluoroalcohol. This new coupling reaction smoothly proceeded with high regiospecificity in regard with QMAs for introducing π-nucleophiles to only the carbon α to the carbonyl group, thereby providing diverse dihydrobenzofurans and derivatives with high yields, up to quantitative, under mild conditions in short reaction times. The choice of Br?nsted acid enabled us to avoid hydrolysis of the QMAs, which gives quinones, and the formation of discrete cationic species from the QMAs. Notably, further investigations in this study with regard to the acid have led to the findings that the originally stoichiometrically used acid could be reduced to a catalytic amount of 5 mol % loading or less and that the stoichiometry of the alkenes could be significantly improved down to only 1.2 equiv. The facts that only a minimal loading (5 mol %) of perfluoroterephthalic acid is required, readily available substrates can be used, and the regioselectivity can be controlled by the acid used make this coupling reaction very fascinating from a practical viewpoint.
Tin tetrachloride-catalyzed regiospecific allylic substitution of quinone monoketals: An easy entry to benzofurans and coumestans
Liu, Yingjie,Liu, Jingxin,Wang, Mang,Liu, Jun,Liu, Qun
supporting information, p. 2678 - 2682 (2013/01/15)
A highly regioselective allylic substitution of quinone monoketals with a-oxoketene dithioacetals is achieved under the catalysis of only tin tetrachloride (1 mol%). The advantages of the reaction, including its simplicity, rapidity, low catalyst loading of inexpensive tin tetrachloride, mild conditions and; in particular, the regiospecificity, is proposed to be due to a pseudo-intramolecular process. This new synthetic method provides a facile [3+2] cycloaddition route to benzofurans and is highlighted by the synthesis of coumestans.
