An efficient, enantioselective rhodium-catalyzed addition of potassium alkenyltrifluoroborates to N-nosyl aliphatic imines has been realized. Good reaction yields and excellent enantioselectivities (94-99% ee) were obtained for a variety of aliphatic imines and nucleophilic alkenyltrifluoroborates. An active rhodium-diene catalyst and the precise reaction condition control proved to be pivotal for success.