Catalytic [4+2] cyclization of α,β-unsaturated acyl chlorides with 3-alkylenyloxindoles: highly diastereo- and enantioselective synthesis of spirocarbocyclic oxindoles

Cinchona alkaloids were used as Lewis base catalysts in the title reaction. The [4+2] cyclization of α,β-unsaturated acyl chlorides with electron-deficient alkenes derived from oxindole gave the corresponding spirocarbocyclic oxindoles.