One-pot pyrrolidine-catalyzed synthesis of benzopyrans, benzothiopyranes, and dihydroquinolidines

A simple catalytic racemic synthesis of benzopyranes, benzothiopyranes and 1,2-dihydroquinolines is presented. The organocatalytic domino reactions between 2-heteroatom substituted aldehyde derivatives and α,β-unsaturated aldehydes or α,β-unsaturated cyclic ketones proceed with excellent chemoselectivity to give the corresponding products in good to high yields.