| 摘要 |
NEW MATERIAL:A cyclopropane derivtive of formula I (R<1> is alkyl, aryl; R<2> is H, silyl; X is halogen). EXAMPLE:Ethyl 2-(1-Triethylsiloxy-2,3,3-trifluoro-2-propenyl-3,3-dimethyl-cyclo propanecarboxylate. USE:A synthetic intermedite of chrysanthemum acid bearing a polyhalomethyl group on the olefin position such as 2-(2-chloro-3,3,3-trifluoro-1-propenyl)-3,3- dimethylcyclopr-opanecarboxylic ester, which is used as a synthetic intermediate of fluorine-containing pyrethroid insecticides. PREPARATION:For example, the reaction of a compound of formula II (R<2>' is silyl) with a polyhalovinyl silane of formula III is effected in the presence of a fluorine an ion source to give a compound of formula I where R2 is silyl, then solvolysis is effected using a protonic solvent in the presence of an acid to give a compound of formula I where R<2> is H.
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