The study of the leaving sulfonyl group and the other N-protecting groups in 1aw–aak^ab.

^aReaction conditions: 1aw–aak (0.1 mmol) and PC 2 (2.0 mol%) were added to degassed MeCN (2.0 mL) under an Ar atmosphere for 12.0 h, in a sealed tube using 385 nm LED light irradiation.

^bNMR yield using 1,3,5-trimethoxybenzene as an internal standard.