Hypervalent Iodine Promoted Selective [2 + 2 + 1] Cycloaddition of Aromatic Ketones and Methylamines: A One-Pot Access to 1-Pyrrolines.

Herein, a versatile highly regioselective three-component annulation of simple aromatic ketones and methylamines using a hypervalent iodine reagent for polyarylated 1-pyrrolines has been described in good to excellent yields. Meanwhile, unsymmetrical 1-pyrroline isomers could be realized and synthesized. Such an intriguing one-pot two-step tandem assembly strategy with green conditions and high regioselectivity shows predictable inspiration in related annulation reactions.