- A Stereoselective Arylative-Cyclopropanation Process
-
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
- Coulibali, Siomenan,Deruer, Elsa,Godin, Elizabeth,Canesi, Sylvain
-
supporting information
p. 1188 - 1191
(2017/03/14)
-
- Synthesis of o-chlorophenols via an unexpected nucleophilic chlorination of quinone monoketals mediated by N,N′-dimethylhydrazine dihydrochloride
-
An unexpected nucleophilic chlorination of a quinone monoketal while carrying out a pyrazolidine synthesis has led to a general preparation of multisubstituted phenols. The products are obtained in good to high yields under mild conditions. The bridged pyrazolidines that were the original targets are obtained in the presence of a protic solvent. This journal is the Partner Organisations 2014.
- Yin, Zhiwei,Zhang, Jinzhu,Wu, Jing,Green, Riana,Li, Sihan,Zheng, Shengping
-
supporting information
p. 2854 - 2858
(2014/05/06)
-
- 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
-
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.
- Hu, Yinjun,Kamitanaka, Tohru,Mishima, Yusuke,Dohi, Toshifumi,Kita, Yasuyuki
-
p. 5530 - 5543
(2013/07/26)
-
- Double hetero-Michael addition of N -substituted hydroxylamines to quinone monoketals: Synthesis of bridged isoxazolidines
-
A general synthesis of bridged isoxazolidines from a double hetero-Michael addition of N-substituted hydroxylamines to quinone monoketals has been developed. The different addition order of N-benzylhydroxylamine and N-Boc hydroxylamine is also discussed.
- Yin, Zhiwei,Zhang, Jinzhu,Wu, Jing,Liu, Che,Sioson, Kate,Devany, Matthew,Hu, Chunhua,Zheng, Shengping
-
supporting information
p. 3534 - 3537
(2013/08/23)
-
- Tin tetrachloride-catalyzed regiospecific allylic substitution of quinone monoketals: An easy entry to benzofurans and coumestans
-
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.
- Liu, Yingjie,Liu, Jingxin,Wang, Mang,Liu, Jun,Liu, Qun
-
supporting information
p. 2678 - 2682
(2013/01/15)
-
- [3 + 2] coupling of quinone monoacetals by combined acid-hydrogen bond donor
-
The expeditious and efficient [3 + 2] coupling approach of quinone monoacetals 1 with alkene nucleophiles 2 by the action of an activated Bronsted acid in the presence of a hydrogen bond donor perfluorinated alcohol has been achieved. With the optimized combined acid, the reaction could proceed under mild conditions by only mixing the two reactants to afford the cycloadducts 3 in a short time (within 10 min) with good to quantitative yields.
- Dohi, Toshifumi,Hu, Yinjun,Kamitanaka, Tohru,Washimi, Naohiko,Kita, Yasuyuki
-
supporting information; experimental part
p. 4814 - 4817
(2011/11/13)
-
- A double oxidation procedure for the preparation of halogen-substituted para-benzoquinone monoketals: Asymmetric synthesis of (-)-harveynone
-
The double oxidation of halophenols with hypervalent iodine reagents in methanol provides a simple procedure to prepare halo-1,4-benzoquinone monoketals. Seven examples of this procedure are reported as is the conversion of 3-iodo-4,4-dimethoxycyclohexa-2
- Hookins, Daniel R.,Taylor, Richard J.K.
-
experimental part
p. 6619 - 6621
(2011/02/21)
-
- Bromide-assisted oxidation of substituted phenols with hydrogen peroxide to the corresponding p-quinol and p-quinol ethers over WO4 2--exchanged layered double hydroxides
-
A simple and efficient one-pot synthesis of p-quinols and their ethers occurs over tungstate-exchanged layered double hydroxides (WO4 2--LDHs), which catalyze the bromide-assisted oxidation of substituted phenols to the corresponding 4-alkoxy- and 4-hydroxycyclohexa-2,5- dienones in high yields (see scheme).
- Sels,De Vos,Jacobs
-
p. 310 - 313
(2007/10/03)
-