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 ?,?-unsaturated aldehydes or ?,?-unsaturated cyclic ketones proceed with excellent chemoselectivity to give the corresponding products in good to high yields