Temperature-Controlled Selectivity toward [1,3]- or [3,3]-Sigmatropic Rearrangement: Regioselective Synthesis of Substituted 3,4-Dihydrocoumarins

Either [1,3]- or [3,3]-sigmatropic rearrangements were selectively accessed by controlling the reaction temperature ill the gold(III)-catalyzed tandem rearrangement/cyclization of (E)-2-(aryloxymethyl)alk-2-enoates to afford diversely substituted 3,4-dihydrocoumarin derivatives in moderate to good yields and in excellent regioselectivity.