In a 3000 mL round bottom flask, a methanol (600 mL) solution of ethyl cis-2-phenylcyclopropane-1-carboxylate (120 g, 0.63 mol, 1.00 eq.) was added, followed by a slow addition of a methanol (600 mL) solution of potassium hydroxide (177 g, 3.16 mol, 5.00 eq.). The reaction mixture was stirred at room temperature for 5 hours. Upon completion of the reaction, the reaction solution was concentrated in vacuum by rotary evaporator. The concentrated residue was diluted with 1000 mL of deionized water and the pH was adjusted to 2 with 2 M hydrochloric acid solution. the aqueous phase was extracted with dichloromethane (3 x 1000 mL), the organic layers were combined and washed with brine (1 x 1500 mL). Finally, the organic layer was concentrated in vacuum to give 2-phenylcyclopropanecarboxylic acid (100 g, 98% yield) as a white solid.
