Fig. 3
From: Enantiodivergence by minimal modification of an acyclic chiral secondary aminocatalyst
Mannich reaction of trifluoromethyl alkynyl ketimines. Reaction conditions for the formation of (S,R)-5: 4 (0.1 mmol), PNBA (0.02 mmol, 20 mol %), Ia/0.5TfOH (20 mol %), 2 (0.3 mmol), MeCN (0.8 mL), −20 °C. Reaction conditions for the formation of (R,S)-5: 4 (0.1 mmol), PNBA (0.02 mmol, 20 mol %), Id/0.5TfOH (20 mol %), 2 (0.3 mmol), MeOH (0.8 mL), −20 °C. Single asterisk (*): Without PNBA as the additive. Double asterisks (**): Without PNBA as the additive. MeCN as the solvent (The absolute and relative configuration of 5k was determined by comparison with the reported ref. 50.)
