To demonstrate the efficacy of the radical reactions, gramscale synthesis and isolation of the reaction products were then investigated (Figure ) by utilizing the low solubility of fumaric acid. Owing to the higher solubility of the radical initiator, cysteine derivatives, and unreacted maleate in aqueous solutions, the gram-scale synthesis afforded fumaric acid in a good yield of 78% (1.82 g) as a white solids, with the melting point of 289-293 ℃ (literature m.p.: 286-287 ℃) . The conventional molecular catalyst of thiourea showed almost no reaction under identical neutral conditions (Figure ).