A mixture of 3.3 g of (1R,3R) 2,2-dimethyl-3-(2,2-dibromoethenyl)-cyclopropane-1-carboxylic acid, 2.2 g of the product of Step A, 1.5 g of potassium carbonate, 100 mg of 1,4,7,10,13,16-hexaoxacyclooctadecane and 50 ml of methyl ethyl ketone wasrefluxed for 24 hours and was evaporated to dryness under reduced pressure.The residue was added to water and the aqueous mixture was extracted with ethyl acetate. The organic phase was evaporated to dryness under reduced pressure and the residue was chromatographed over silica gel. Elution withbenzene yielded 2.84 g of [5-phenoxy-(1,2,4)-thiadiazol-3-yl]-methyl (1R,3R) 2,2-dimethyl-3-(2,2-dibromoethenyl)-cyclopropane-1-carboxylate.
