Optimization studies were performed using chromone-3-carboxylic acid 1a and optically active (R)-2-phenyl-1-tosylaziridine 2a as model substrates (Table ). Initial experiment was performed in NMP as solvent in the presence of tetrabutylammonium iodide (TBAI) as a radical mediator under LED irradiation and under inert atmosphere. To our delight, the desired decarboxylative cross-coupled product 3a was formed in low yield with exclusive regioselectivity (Table , entry 1). Importantly, the optical purity of 2a was partially preserved under the reaction conditions. Therefore, solvent screening was initiated to increase both the efficiency and stereospecificity of the process (Table , entries 1-5). Among tested solvents, the best results were obtained using anhydrous N,N-dimethylformamide (Table , entry 2). Next, the influence of halogen source on the reaction outcome was assessed (Table ). Both inorganic and organic iodides initiated the reaction (Table , entries 2,6,7). However, worser efficiency and stereospecificity was observed in the case of inorganic salts (Table , entries 6,7). Moreover, it was found that the replacement of the counterion with the bromide or fluoride ions suppressed the reactivity (Table , entries 8,9). In subsequent investigations, reducing the amount of TBAI from 2 to 1.5-fold excess, yielded the desired product in lower 46% yield (Table , entry 10). Using 3-fold excess of TBAI did not improve the reaction efficiency (Table , entry 11). In a course of further studies, the concentration effect was evaluated (Table , compare entries 12,13). It was found that the decarboxylative cross-coupling reaction proceeded with higher efficiency at higher concentration (Table 1, entry 13) providing 3a with a high 84% yield and with high degree of preservation of optical purity (Table 1, entry 13).