CuI–Fesulphos complexes: efficient chiral catalysts for asymmetric 1,3-dipolar cycloaddition of azomethine ylides

The CuI–Fesulphos catalyst system (≤3 mol %) shows an excellent performance in the asymmetric 1,3-dipolar cycloaddition of azomethine ylides. High to very high levels of reactivity, endo/exo selectivity, and enantioselectivity (69–>99% ee) are generally achieved with a very wide range of azomethine ylides and dipolarophiles. Based on experimental and computational studies data, a model that accounts for this high enantiocontrol is proposed.