A lithium methoxide-catalyzed hetero Diels–Alder reaction of aromatic and aliphatic aldehydes with 1-methoxy-3-trimethylsilyloxy-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.
[reaction: see text] The first catalytic, asymmetric 2,3-trans-selective heteroDiels-Alderreaction has been developed. The reactions of aldehydes with Danishefsky'sdienes proceeded smoothly to afford the pyranone derivatives in high yields with high trans-selectivities and enantioselectivities in the presence of a chiral zirconium complex, which was prepared from zirconium tert-butoxide and (R)-3
Hetero Diels-Alder Type Reactions Between Danishefsky’s Dienes in the Presence of Lewis Base Catalysts. An Efficient Method for the Synthesis of Substituted 2,3-Dihydropyran-4-ones