Enantioselective synthesis of 8-azabicyclo[3.2.1]octanes via asymmetric 1,3-dipolar cycloadditions of cyclic azomethine ylides using a dual catalytic system.

The first example of asymmetric 1,3-dipolar cycloadditions between diazo imine-derived cyclic azomethine ylides and acryloylpyrazolidinone using a rhodium(ii) complex/chiral Lewis acid binary system is reported. The asymmetric cycloadditions afforded optically active 8-oxabicyclo[3.2.1]octanes with high diastereo- and enantioselectivities (up to >99 : 1 dr, 99% ee). A switch of exo/endo-selectivity was observed depending on the diazo substrates.