[Cl:1][C:2]([Cl:8])=[CH:3][CH:4]=[C:5]([CH3:7])[CH3:6].Br[CH:10]([C:16]#[N:17])[C:11]([O:13][CH2:14][CH3:15])=[O:12].C[O-].[Na+]>CO.[Cu]>[C:16]([C:10]1([C:11]([O:13][CH2:14][CH3:15])=[O:12])[CH:4]([CH:3]=[C:2]([Cl:8])[Cl:1])[C:5]1([CH3:7])[CH3:6])#[N:17]
A mixture of 1,1-dichloro-4-methylpenta-1,3-diene (15.1 parts), copper-containing catalyst in amount indicated in the table below and methanol (32 parts) is heated to reflux and ethyl bromocyanoacetate (19.2 parts) in methanol (14 parts) is then added at a uniform rate during 6 hours, and the acid-base balance ("pH" as indicated by a pH meter) is maintained at a predetermined value by the addition of a 13% solution of sodium methoxide in methanol. On completion of the ethyl bromocyanoacetate addition, heating at reflux temperature is continued for a further 2 hours, maintaining the desired acid-base balance as necessary. The resulting solution is evaporated under reduced pressure to remove the solvent and the product is isolated as described in Examples 2-6 above. The yield, strength and composition of the ethyl 1-cyano-3-(2',2'-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylate obtained are given in the following table together with other reaction details:
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