At the outset, N-3,4,5-trimethoxyphenyl (TMP)-substituted aldimine 2a and benzothiazoline 3a were mixed in mesitylene in the presence of chiral phosphoric acid (R)-1 under photoirradiation conditions (Table ). Among the chiral phosphoric acids examined, the nitrated BINOL skeleton containing 1a afforded the most favorable result (99%, 90% ee). The nitro groups at the 6,6'-positions of BINOL phosphoric acid were necessary for the high reactivity and enantioselectivity (entries 1-4). The presence of the TMP group on the nitrogen atom of 2a was critical, and the use of N-p-methoxyphenyl (PMP)-substituted aldimine 2a-PMP in place of N-TMPsubstituted aldimine 2a lowered both enantioselectivity and reactivity (entry 5). Mesitylene was found to be the solvent of choice (entries 6 and 7). Furthermore, Hantzsch ester (HE), which is known as an alkyl radical precursor by single-electron oxidation, was not suitable (entry 8). Control experiments clarified that both 1a and photoirradiation were critical to promote the reaction (entries 9 and 10). The enantioselectivity slightly decreased in the absence of MS4A (entry 11). The addition reaction was completely suppressed in air (entry 12). TMP: 3,4,5-trimethoxyphenyl, PMP: p-methoxyphenyl.