A stirred mixture of sodium cyanide (18.0 g, 0.36 mole) and 3-(cyclohexylamino)propanesulfonic acid (1.34 g, 0.006 mole) in 300 ml of water was warmed to 40°. During a one hour period, maintaining a reaction temperature of about 40°, a solution of cis-3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropanecarbonyl chloride (71.7 g, 0.315 mole) and 3-phenoxybenzaldehyde (61.9 g, 0.3 mole) in 262.2 g of n-heptane was added. The mixture was then stirred at 40° for one additional hour, after which it was washed with an aqueous solution containing 20% sodium carbonate and then with water. The organic phase was separated from the mixture and the solvent removed by distillation under reduced pressure to give α-cyano-3-phenoxybenzyl cis-3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropanecarboxylate.
