Herein, a three-step general strategy featuring a thermal intramolecular Diels-Alder (IMDA) reaction to prepare the tricyclic 9-methyl-7-aryl-tetrahydro-6H-benzo[c]chromen-6-one core of morusalisin A is reported. This developed chemistry is applicable to the synthesis of a variety of tricycles, including 9-silyloxy and 9-phenyl-7-aryl-tetrahydro-6H-benzo[c]chromen-6-ones. In addition, a one-pot dehydration/IMDA procedure was demonstrated. The positioning of substituents on the aryldiene moiety played a significant role in governing the endo/exo selectivity, while the overall yield and reaction rate were affected by the electronic properties of both cinnamates and aryldienes. Functional group manipulations of the resulting cycloadducts were performed to furnish synthetically useful derivatives.