A practical, electrochemical method is developed for the direct dehydrogenative lactonization of C(sp2/sp3)–H bonds under external oxidant- and metal-free conditions, delivering diverse lactones, including coumarin derivatives with excellent regioselectivity. The scalable nature of this newly developed electrochemical process was demonstrated on a 40 g scale following an operationally simple protocol
Rhenium-Catalyzed Phthalide Synthesis from Benzamides and Aldehydes via C–H Bond Activation
作者:Bing Jia、Yunhui Yang、Xiqing Jin、Guoliang Mao、Congyang Wang
DOI:10.1021/acs.orglett.9b02142
日期:2019.8.16
The [4 + 1] annulation of benzamides and aldehydes for phthalide synthesis was achieved via rhenium-catalyzed C–H activation, which demonstrates an unprecedented reaction pattern distinct from those of other transition-metal catalyses. The reaction also features readily available starting materials, a wide scope for both electro-rich and electro-deficient substrates, and the elimination of homoannulation
Direct and selective synthesis of 3-arylphthalides via nickel-catalyzed aryl addition/intramolecular esterification
作者:Qing Qiang、Feipeng Liu、Zi-Qiang Rong
DOI:10.1016/j.tet.2021.132162
日期:2021.6
Herein we report a nickel-catalyzed aryl addition/intramolecular esterification in a cascade fashion. Under the combination of commercially available nickel precursor and tridentate ligand, the one pot protocol offers a direct, simple and regioselective approach to access 3-aryl phthalide derivatives from two readily available substrates with good efficiency, broad scope as well as satisfactory functional
A rhodium or palladium-catalyzedaddition of boronic acids to phthalaldehydonitrile, followed by an intramolecularlactonization of cyano to access 3-substituted phthalides, is described. This procedure tolerates a series of functional groups, such as methoxy, fluoro, chloro, and vinyl groups. It is a novel procedure for the synthesis of 3-arylphthalides.
A palladium-catalyzedaddition of arylboronic acids to phthalaldehyde, followed by an intramolecularlactonization to access 3-substituted phthalides, is described. The procedure tolerates a series of functional groups, such as methoxyl, fluoro, chloro, and trifluoromethyl groups. It represents a procedure for the synthesis of 3-substituted phthalides.