An L-tert-leucine derived urea catalyzed asymmetric synthesis of acylclic N, N '-ketals derived from aryl amines and isatin-derived ketimines

An asymmetric synthesis of N,N'-ketal compounds derived from isatin-derived ketimines and aryl amines has been developed using an inexpensive and readily available L-tert-leucine derived urea catalyst. Using this asymmetric catalytic synthetic method, a series of 3-substituted 3-amino-2-oxoindole derivatives containing an N,N'-ketal motif were obtained in high yields with high enantioselectivities. (C) 2021 Elsevier Ltd. All rights reserved.