Figure 2.

Design plan and optimization of the reaction conditions used in the preparation of β-selenolated Leu. (A) Symmetric Giese reaction via photoredox catalysis. (B) Standard conditions: PC (1 mol %), 2a (1.2 equiv), HE (1.5 equiv), DIPEA (2.0 equiv), DCM, blue LED (10 W), 25 °C. Legend: (a) 18 h; (b) 48 h; (c) isolated yield; (d) diastereoselectivity determined by 1H NMR and GC analysis of the crude reaction mixture. Abbreviations: PC, photoredox catalyst; HE, Hantzsch ester; DIPEA, N,N-diisopropylethylamine; DCM, dichloromethane; DMF, N,N-dimethylformamide.