Fig. 2: Substrate scope of α-alkynyl ketones.

Reactions were performed with 1 (0.2 mmol), 2a (0.22 mmol), CPA (S)-A9 (0.02 mmol), activated 4 Å MS (200 mg) in CCl₄ (2 mL) at room temperature. Isolated yields. Er values were determined by HPLC analysis on a chiral stationary phase.