Acid-free, aminoborane-mediated Ugi-type reaction leading to general utilization of secondary Amines

[GRAPHICS] A variety of secondary amines have become utilized in the Ugi reaction by using aminoborane 1 as an iminium ion generator. Aldehydes, secondary amines, and isocyanides are coupled in the presence of 1 at room temperature, giving the corresponding alpha-amino amides in good yields. The nonacidic reaction conditions are beneficial for unique chemoselectivity, where the aldimine functionality is left intact in the present Ugi-type reaction.