Direct deprotonation represents an extremely simple, straightforward, and atom‐economic strategy to activate pronucleophiles bearing an acidic proton. However, the difficulty often arises in activating pronucleophiles with high pKa values by using conventional chiral tertiary amines. To overcome this challenge, a handful of novel chiral Brønsted superbases, including amidines, guanidines, cyclopropenimines, and iminophosphoranes, have been discovered in recent years. This minireview focuses on the application of these organo‐superbases in the catalytic asymmetric reactions of weakly acidic pronucleophiles, and highlights their comparison to the conventional tertiary amines, demonstrating the highly efficient deprotonation processes and stereoselectivity controlled conversions of the superbases. The advantage of these new superbases brings a great opportunity for developing more asymmetric transformations of weakly acidic pronucleophiles.

Azacycles such as indoles and tetrahydroquinolines are privileged structures in drug development. Reported here is an unprecedented regiodivergent intramolecular nucleophilic addition reaction of imines as aflexible approach to access Nfunctionalizedindoles and tetrahydroquinolines,bythe control of reaction at the N-terminus and C-terminus,r espectively. Using ketimines derived from 2-(2-nitroethyl)anilines with isatins or a-ketoesters,t he regioselective N-attackr eaction gives N-functionalized indoles,w hile the catalytic enantioselective C-attackr eaction affords chiral tetrahydroquinolines featuring an a-tetrasubstituted stereocenter.M echanistic studies reveal that hydrogen-bonding interactions may greatly facilitate such unusual N-attackreactions of imines.The utility of this protocol is highlighted by the catalytic enantioselective formal synthesis of (À)-psychotrimine,and the construction of various fused aza-heterocycles. Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.org/10.1002/anie.201910864. Angewandte Chemie Research Articles Scheme 1. Reaction design and development. M.S. = moleculars ieves, Ts = 4-toluenesulfonyl.Figure 8. Synthetic applicationsofN-functionalized indole derivatives. X-ray structure for 21 shown. [36] AIBN = 2,2'-azobis(isobutyronitrile), LAH = lithium aluminumhydride, Ns = 4-nitrobenzenesulfonyl, TEA = triethylamine.

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