All the NHC precatalysts and aldehydes 1 were purchased.
Aldehydes1a –c were solids in a pure
form at room temperature: mp 45–46 °C for1a , 54–56 °C for 1b , and 57–59 °C
for1c . The enantiomeric purities of 2a–c were determined by HPLC using a chiral column (Daicel), and the
absolute configurations were determined by comparison with the signs
of the reported specific rotation values.
Aldehydes
form at room temperature: mp 45–46 °C for
for
absolute configurations were determined by comparison with the signs
of the reported specific rotation values.