Lewis Acid Catalyzed [1,3]-Sigmatropic Rearrangement of Vinyl Aziridines

The authors reported (Rapid Synthesis of Psychoplastogenic Tropane Alkaloids) the application of Njardarson and co-workers' vinyl aziridine rearrangement conditions (5% Cu(hfacac)2, PhMe, 150 °C) to their intermediates 13a and 13b in a tropane alkaloid synthesis (substrates not covered in the original work). However, these conditions gave only limited conversion to 14a (36% yield) and 14b (19% yield), respectively, with significant decomposition of the starting material. Later the authors found conditions to raise the yield of these intermediates.