Palladium(II)-catalyzed tandem annulation reaction of o-alkynylbenzoates with methyl vinyl ketone for the synthesis of isocoumarins
作者:Huan Wang、Xiuling Han、Xiyan Lu
DOI:10.1016/j.tet.2013.07.057
日期:2013.10
A palladium(II)-catalyzed highly regioselective tandem reactions of o-alkynylbenzoates with methyl vinyl ketone for the synthesis of isocoumarins was developed. It is a convenient, mild and environmentally benign reaction with moderate to high yield. The reaction is initiated by the Pd(II) species and regenerate the Pd(II) species to complete the catalytic cycle without the necessity of a redox system
4-Chloroisocoumarins can be conveniently prepared from 2-alkynylaryloate esters via the activation of alkynes by electrophilic chlorine, generated in situ from N-chlorosuccinimide (NCS) in the presence of 10 mol % trimethylsilyl chloride (TMSCl), which leads to 6-endo-dig-selective chlorinative annulation to give the desired products in moderate to quantitative yields. The procedure employs readily
(Trifluoromethyl)thiolation of 2-Alkynylbenzoates: An Efficient Route to 4-[(Trifluoromethyl)thio]-1<i>H</i>-isochromen-1-ones
作者:Yuewen Li、Guangming Li、Qiuping Ding
DOI:10.1002/ejoc.201402629
日期:2014.8
The incorporation of the (trifluoromethyl)thio group into the isocoumarin scaffold through a Lewis-acid-mediated electrophilic cyclization reaction of 2-(2-alkynyl)benzoates with trifluoromethanesulfanylamide is reported. The transformation proceeds well in the presence of BiCl3 and BF3·Et2O under mild conditions to give 4-[(trifluoromethyl)thio]-1H-isochromen-1-ones regioselectively and in good yields
In Situ Formation of RSCl/ArSeCl and Their Application to the Synthesis of 4-Chalcogenylisocumarins/Pyrones from <i>o</i>-(1-Alkynyl)benzoates and (<i>Z</i>)-2-Alken-4-ynoates
作者:Linlin Xing、Yong Zhang、Bing Li、Yunfei Du
DOI:10.1021/acs.orglett.9b01046
日期:2019.5.17
diorganyl disulfides or diselenides with PhICl2 in acetonitrile was found for the first time to lead to the in situ formation of organosulfenyl chloride or selenenyl chloride, which enables the regioselective intramolecular chalcogenylacyloxylation of alkynes resulting in the formation of 4-chalcogenylisocumarins/pyrones in good to excellent yields under metal-free conditions.
Facile synthesis of sulfenyl-substituted isocoumarins, heterocycle-fused pyrones and 3-(inden-1-ylidene)isobenzofuranones by FeCl3-promoted regioselective annulation of o-(1-alkynyl)benzoates and o-(1-alkynyl)heterocyclic carboxylates with disulfides
作者:Zhen Li、Jianquan Hong、Linhong Weng、Xigeng Zhou
DOI:10.1016/j.tet.2011.12.003
日期:2012.2
Reported herein is the FeCl3-promoted intermolecular sulfoesterification of o-(1-alkynyl)benzoates with disulfides, which provides a convenient and efficient method for synthesis of 4-sulfenylisocoumarins. Various functional groups such as methoxy, halides, ester, cyano and silicon groups in the substrates are tolerated, and heterocycle-fused chalcogenylpyrones are also successfully achieved directly