Enantioselective Synthesis of Pyrroloindolines by a Formal [3+2] Cycloaddition Reaction

(R)-BINOL center dot SnCl4 was found to catalyze a formal [3 + 2] cycloaddition reaction between C(3)-substituted indoles and 2-amidoacrylates to provide pyrroloindolines. A variety of pyrroloindolines were prepared with high enantioselectivity in one step from simple precursors. This methodology is expected to facilitate the total synthesis of pyrroloindoline alkaloids, an important class of biologically active natural products.