Oxidative Phosphonylation of Aromatics with Ammonium Cerium(IV) Nitrate Arylphosphonates 5 and 6 can be prepared in good yields in a one-step synthesis starting from arenes with tri- or diethylphosphites and cerium ammonium nitrate (CAN) as oxidant. The selectivity of the oxidative phosphonylation is relatively low; the reactive species is a phosphite radical cation.
Manganese(III)-mediated direct phosphonylation of arenes
作者:Wei Xu、Jian-Ping Zou、Wei Zhang
DOI:10.1016/j.tetlet.2010.03.029
日期:2010.5
Manganese (III)-promoted direct phosphonylation of mono- and disubstituted arenes with dialkylphosphite afforded regioselective dialkylphosphonates in good yields. The reactions can apply to arenesbearing electron-donating groups and electron-withdrawinggroups such as ester and nitrile.
anodic oxidation proceeds either via phosphiniumradicalcations, which then attack the arenes electrophilically, or via arene radicalcations, which add the trialkylphosphite as nucleophile. Aryl phosphonates are also obtained in good yield by chemical oxidation with peroxodisulfate/AgNO3 in acetonitrile/water or glacial acetic acid. The diethylphosphinium radicalcation, formed from diethylphosphite by
The effect of substituents in SRNl reactions. Some synthetic applications
作者:Joseph F. Bunnett、Eric Mitchel、Carlo Galli
DOI:10.1016/s0040-4020(01)97188-1
日期:1985.1
Most of the ortho effects are slight, but there is evidence that large ortho substituents hinder attachment of the phosphite more than the enolate nucleophile. The methoxy and diethoxyphosphoryl substituents, when para to the site of substitution, respectively favour and disfavour the phosphite with respect to the enolate ion. SRNl reactions of ortho-substituted halobenzenes are, for some substituents