1443006-74-3Relevant articles and documents
Synthesis of cyclopentenimines from N-allyl ynamides via a tandem aza-Claisen rearrangement-carbocyclization sequence
Wang, Xiao-Na,Winston-Mcpherson, Gabrielle N.,Walton, Mary C.,Zhang, Yu,Hsung, Richard P.,Dekorver, Kyle A.
, p. 6233 - 6244 (2013/07/26)
We describe here details of our investigations into Pd-catalyzed and thermal aza-Claisen-carbocyclizations of N-allyl ynamides to prepare a variety of α,β-unsaturated cyclopentenimines. The nature of the ynamide electron-withdrawing group and β-substituent plays critical roles in the success of this tandem cascade. With N-sulfonyl ynamides, the use of palladium catalysis is required, as facile 1,3-sulfonyl shifts dominate under thermal conditions. However, since no analogous 1,3-phosphoryl shift is operational, N-phosphoryl ynamides could be used to prepare similar cyclopentenimines under thermal conditions through zwitter ionic intermediates that undergo N-promoted H-shifts. Alternatively, by employing ynamides bearing tethered carbon nucleophiles, the zwitter ionic intermediates could be intercepted, giving rise rapidly to more complex fused bi- and tricyclic scaffolds.
