Organocatalytic Asymmetric Michael/Friedel–Crafts Cascade Reaction of 3‑Pyrrolyl-oxindoles and α<i>,</i>β‑Unsaturated Aldehydes for the Construction of Chiral Spiro[5,6-dihydropyrido[1,2‑<i>a</i>]pyrrole-3,3′-oxindoles]

An efficient and unprecedented organocatalytic asymmetric reaction of 3-pyrrolyl-oxindoles with α,β-unsaturated aldehydes to generate spirocyclic oxindole compounds was developed. The reactions were catalyzed by diphenylprolinol silyl ether and 2-fluorobenzoic acid via an asymmetric Michael/Friedel–Crafts cascade process, followed by dehydration with p-toluenesulfonic acid to afford a wide variety of structurally diverse spiro­[5,6-dihydropyrido­[1,2-a]­pyrrole-3,3′-oxindole] derivatives in high yields (up to 93%) and with high to excellent diastereo- and enantioselectivities (up to >99:1 dr and 97% ee).