Process to bicyclic lactones
AssigneeFMC Corporation
InventorsKiyoshi Kondo, Toshiyuki Takashima, Daiei Tunemoto
Life of this patent
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Abstract
Lactones of the formula ##STR1## wherein R is hydrogen or a CX.sub.3 group, and each X is a chlorine or bromine atom, are converted to the known cis-3-(2,2-dihalovinyl)-2,2-dimethylcyclopropanecarboxylic acids or lower alkyl esters, from which pyrethroid insecticides are obtained.
Claims5
A process for preparing a lactone of the formula ##STR10## wherein each X is a chlorine or bromine atom, R is hydrogen or a lower alkoxycarbonyl group, and the lactone is the (1R,4R,5S) isomer, the (1S,4S,5R) isomer, or a mixture thereof, which comprises cyclizing a diazo ester of the formula ##STR11## by heating in the presence of a copper-containing catalyst, thereby producing said lactone.
Dependencies are inferred from the claim text.