Lewis Acid-Promoted Carbon-Carbon Bond Cleavage of Aziridines: Divergent Cycloaddition Pathways of the Derived Ylides

摘要

The chemistry of aziridines is dominated by the reactivity of the carbon-nitrogen bonds. The most notable exception to this reactivity pattern is the thermal or photochemical electrocyclic ring opening of aziridines to give azomethine ylides as transient intermediates resulting from carbon-carbon bond cleavage. This reaction manifold enjoys a prominent role in pyrrolidine synthesis due to the facility with which the derived 1,3-dipoles may be trapped in [3 + 2] cycloaddition reactions; however, the development of mild variants of this C-C bond heterolysis is largely unexplored. Herein, we document reaction conditions that, to the best of our knowledge, achieve the first productive cycloadditions of azomethine ylides obtained from Lewis acid-promoted carbon-carbon bond cleavage of aziridines. The constitution of the cycloadduct obtained is further shown to be strongly dependent on the identity of the alkene trap employed.