AnN,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
The enantioselectiveStreckerreaction of N-diphenylphosphinoyl ketoimines has been achieved by use of in situ prepared chiral N,N‘-dioxide catalyst from l-piperidinamide 3f and m-chloroperoxybenzoic acid (m-CPBA). Excellent yields (up to 99%) and high enantioselectivities (up to 92% ee) were obtained. In particular, in situ prepared catalyst with readily available chiral material made the procedure