Dimethyl 2-phenylcyclopropane-1,1-dicarboxylate could be produced through the following synthetic routes.

A. Bis(methoxycarbonyl)(phenyliodinio)methanide (1). A 1-L, 3-necked round-bottomed flask equipped with a 3-cm oval -coated magnetic stir bar is fitted with a gas inlet adapter connected to a nitrogen line and a gas bubbler, and a septum through which is inserted a thermocouple probe. The third neck is fitted with a ground glass stopper, which is removed for solvent and solids additions. To the flask is added potassium hydroxide (30.2 g, 85%, 0.45 mol, 5.0 equiv) and acetonitrile (300 mL). The solution is cooled to 5 °C with an ice/ bath and then dimethyl malonate (11.9 g, 90.0 mmol, 1.00 equiv) is added via a weighed 20-mL syringe over 5 min, forming a viscous slurry. PhI(OAc)₂ (32.0 g, 99.3 mmol, 1.10 equiv) is added in one portion. The viscous heterogeneous mixture is stirred vigorously for 2 h at 0 to 5 °C and gradually becomes a viscous creamy suspension. Water (150 mL) is added in one portion, resulting in a temperature rise to 10 °C. The mixture is stirred for 2 min at this temperature, then filtered through a 350-mL medium porosity sintered glass funnel. The flask is rinsed with room temperature water (100 mL), and this rinse is used to slurry wash the filter cake. The cake is washed a second time with water (100 mL). The white solid is next slurry-washed with Et₂O (150 mL). The solids are dried to constant weight under vacuum (20 mmHg) at 30 °C for 25 h to afford bis(methoxycarbonyl)(phenyliodinio)methanide 1 (23.9 g, 79 %) as an off-white crystalline solid.

B. Dimethyl 2-phenylcyclopropane-1,1-dicarboxylate (2). A 250-mL 3-necked round-bottomed flask equipped with a 2-cm oval Teflon-coated magnetic stir bar is fitted with a gas inlet adapter connected to a nitrogen line and a gas bubbler, and a septum through which is inserted a thermocouple probe. The third neck is fitted with a ground glass stopper, which is removed for solvent and solids additions. To the flask is added bis[rhodium(α,α,α',α'-tetramethyl-1,3-benzenedipropionic acid)] (5 mg, 0.007 mmol, 0.02 mol %), dichloromethane (80 mL) and styrene (3.90 g, 37.4 mmol, 1.00 equiv), and the stirred solution is cooled to 2 °C using an ice/water bath. Iodonium ylide 1 (14.7 g, 43.9 mmol, 1.2 equiv) is added in four portions (3.5 - 4.0 g each) at 5 min intervals. After the last addition, the ice/water bath is removed. The mixture is allowed to warm to room temperature and is stirred for 1 h at 18-20 °C. Aqueous 10% thiourea (50 mL) is added in one portion and the biphasic solution is stirred for 15 min at 20 °C. The mixture is transferred to a 250-mL separatory funnel along with a dichloromethane rinse (15 mL) of the flask. The layers are separated and the aqueous layer is extracted with dichloromethane (2 × 20 mL). The organic layers are combined and vacuum filtered through a bed of Na₂SO₄ (20 g) on top of a Celite(c) cake (20 g) in a 150-mL sintered-glass funnel. The cake is washed with dichloromethane (2 × 50 mL). The filtrate is concentrated by rotary evaporation (40 °C bath, 100 mmHg initial, lowered to 20 mmHg) to afford 18 g of a yellow, oily mixture of cyclopropane 2 and iodobenzene. This oil is purified by chromatography on SiO₂ to afford dimethyl 2-phenylcyclopropane-1,1-dicarboxylate (2) (8.07-8.34 g, 92-95% yield) as a yellowish oil.