Synthesis of 4-pyrrolin-2-ones
The common organo-photocatalyst Eosin Y shows excellent catalytic activities for thermal redox reactions under a catalytic amount of Cu(OAc)2 too. Using this catalytic system, a formal [3 + 2] cycloaddition of vinyl azides and ketene silyl acetals provides five-membered ene-γ-lactams and bridge ring lactams via an α-ester radical addition without light irradiation.
W.-L. Lei, K.-W. Feng, T. Wang, L.-Z. Wu, Q. Liu, Org. Lett., 2018, 20, 7220-7224.
A copper-catalyzed annulation of oxime acetates and α-amino acid ester derivatives provides 4-pyrrolin-2-ones bearing a 3-amino group. This process features the oxidation of amines with oxime esters as the internal oxidant and a subsequent nucleophilic cyclization.
C.-B. Miao, A.-Q. Zheng, L.J. Zhou, X. Lyu, H.-T. Yang, Org. Lett., 2020, 22, 3381-3385.