Fig. 4.

Substrate scope of tertiary α-bromoketones. Reactions were performed with 7 (0.1 mmol), 2 (0.2 mmol), DPZ (0.1 × 10⁻³ mmol), C2/C3/C4 (0.02 mmol), NaHCO₃ (0.3 mmol), and 5 Å MS (50 mg) in 1,2-dimethoxyethane (1.5 mL) at 0 °C. Yields were determined based on the isolated material after chromatographic purification. Enantiomeric excesses were determined by HPLC analysis on a chiral stationary phase