A lithium methoxide-catalyzed hetero Diels-Alder reaction of aromatic and aliphatic aldehydes with 1-methoxy-3-tri-methylsilyloxy-1,3-butadiene (Danishefsky's diene) is described. It proceeds through the Mukaiyama-Aldol reaction pathway and affords the corresponding 2,3-dihydropyran-4-one skeletons in good to excellent yields.