Figure 5: Isotope experiment with [1- 2 H]-phenylglyoxal.

The reaction was performed with [1-2H]-phenylglyoxal (0.1 mmol), 3a (1.0 equiv.), (R)-1d (10 mol%) and KF (2.0 equiv.) at 20 °C.

The reaction was performed with [1-2H]-phenylglyoxal (0.1 mmol), 3a (1.0 equiv.), (R)-1d (10 mol%) and KF (2.0 equiv.) at 20 °C.