Please use this identifier to cite or link to this item: http://hdl.handle.net/20.500.12779/4393
Title: A Novel Method for the Efficient Synthesis of Methyl 2-Oxo-2-arylacetates and Its Application to the Preparation of Fungicidal Methyl (E)-O-Methyloximino-2-arylacetates and their Stereoisomers
Authors: R., Rossi
A., Carpita
P., Pazzi
L., Mannina
Valensin, Daniela 
Keywords: ALPHA-KETO ESTERS; ACIDS; DERIVATIVES; REAGENTS
Issue Date: 1999
Project: None 
Journal: TETRAHEDRON
Abstract: 
Methyl 2-oxo-2-arylacetates 1, which include some fluorinated compounds, have been synthesized in moderate to excellent yields by reaction of methyl oxalyl chloride with arylzinc halides in the presence of Pd(PPh3)(4). The highest yields have been obtained when these reactions involved arylzinc bromides which were prepared by conversion of the corresponding aryl bromides to organolithiums, followed by transmetallation with ZnBr2. Compounds 1 have been converted in high yields to the corresponding (E)- and (Z)-O-methyloximino-2-arylacetates (E)- and (Z)-5 by treatment with O-methylhydroxylamine hydrochloride in pyridine. Compounds (E)and (Z)-5 have been easily separated by MPLC on silica gel and their structure and stereochemistry have been assigned by NMR techniques. So prepared compounds of general formula 5 included an agrochemically important fungicide, i.e. (E)-5c, its fluorinated structural analogues, as well as compounds which proved to be able to delay the growth of fungal species isolated from deteriorated papers. Interestingly, several compounds of general formula (Z)-5 underwent partial stereomutation in the presence of daylight and catalytic amounts of iodine.
Description: 
27085
URI: http://hdl.handle.net/20.500.12779/4393
ISSN: 0040-4020
DOI: 10.1016/S0040-4020(99)00632-8
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