An N,N′‐Dioxide/In(OTf)₃ Catalyst for the Asymmetric Hetero‐Diels–Alder Reaction Between Danishefsky's Dienes and Aldehydes: Application in the Total Synthesis of Triketide

In-teresting catalyst: An asymmetric hetero Diels–Alder reaction between Danishefsky's dienes and various aldehydes using an N,N′-dioxide/In(OTf)3 complex affords highly substituted chiral dihydropyranones with up to 99 % ee (see scheme). The catalyst was applied to the synthesis of triketide from propionaldehyde in 72 % yield and with 97 % ee.