Enantioselective Synthesis of α‑Heteroarylpyrrolidines by Copper-Catalyzed 1,3-Dipolar Cycloaddition of α‑Silylimines
2014-04-18T00:00:00Z (GMT) by
α-Heteroarylpyrrolidines have been efficiently prepared via 1,3-dipolar cycloaddition between silylimines and activated olefins. In the presence of Cu(CH<sub>3</sub>CN)<sub>4</sub>PF<sub>6</sub>/Walphos as catalytic system, high levels of enantioselectivity (up to ≥99% ee) and diastereoselectivity were achieved (major formation of C-2/C-4 <i>trans</i>-substituted pyrrolidines). The reaction is compatible with a broad variety of dipolarophiles including maleimides, maleates, fumarates, nitroalkenes, and vinylsulfones. The resulting cycloadducts can be transformed into bioactive pyrrolidine derivatives.