*3.8. General Procedure for the α-Chlorination of β-Keto Ester 9*

To a mixture of β-keto ester **9** (0.1 mmol, 24.4 mg, ω = 95%), organocatalyst **II**, **III**, **VI**– **VIII**, or **IX** (1 mol%), and K2HPO4 (solid, 1 equivalent, 17.4 mg) in chlorobenzene (2 mL), at −20 ◦C under argon atmosphere, was added *N*-chlorosuccinimide (NCS, 1.2 equivalents, 16 mg), and the reaction mixture was stirred for 2 h at −20 ◦C. After completion, the reaction was quenched by addition of NH4Cl (aq. sat, 4 mL) and extracted with CH2Cl2 (10 mL). The organic phase was dried over anhydrous Na2SO4, filtered, and the volatiles were evaporated in vacuo. The residue was purified by column chromatography (Silica gel 60, EtOAc/*n*-Heptane = 1:12). Enantiomeric excess (ee) was determined by HPLC (Chiralpak OJ-H, *n*-Hexane/*i*-PrOH = 70:30, flow rate 0.7 mL/min, λ = 250 nm, 10 ◦C) isolation with column chromatography (Silica gel 60, EtOAc/*n*-Heptane = 1:12).
