Asymmetric Synthesis of α-Branched Allylic Amines by the Rh(I)-Catalyzed Addition of Alkenyltrifluoroborates to N - tert -Butanesulfinyl Aldimines

The first Rh(I)-catalyzed addition of alkenylboron reagents to imines is described. The Rh(I)-catalyzed addition of potassium alkenyltrifluoroborate salts to both aromatic and aliphatic N-tert-butanesulfinyl aldimines proceeds in good yields (up to 97%) and with very high diastereoselectivities (95:5 to >99:1). This new method enables the general and efficient asymmetric synthesis of the important class of alpha-branched allylic amines from readily available and stable starting materials.