Asymmetric α-Amination of Aldehydes and Ketones Catalyzed by tert-Butoxy-L-Proline

Asymmetric electrophilic α-amination of aldehydes and ketones is described using trans-3-tert-butoxy-Lproline and trans-4-tert-butoxy-L-proline as efficient catalysts. Good yields and high enantioselectivities are obtained working at 0°C or at room temperature with a catalyst loading of only 5 mol%.