This article presents further examples of the enantioselective rhodium-catalyzed addition of potassium allyltrifluoroborates to cyclic imines. A wide range of substituted allyl-trifluoroborates are compatible with this process, and provide protected homoallylic amines with high levels of diastereo- and enantioselection. The reactions display a strong preference for carbon–carbon bond formation at the more substituted terminus of the allyl fragment of the allyltrifluoroborate, regardless of the position of the boron atom. Representative examples of manipulation of the products are also described.
Key words
allyltrifluoroborates - asymmetric catalysis - enantioselectivity - imines - rhodium