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 a flexible approach to access N‐functionalized indoles and tetrahydroquinolines, by the control of reaction at the N‐terminus and C‐terminus, respectively. Using ketimines derived from 2‐(2‐nitroethyl)anilines with isatins or α‐ketoesters, the regioselective N‐attack reaction gives N‐functionalized indoles, while the catalytic enantioselective C‐attack reaction affords chiral tetrahydroquinolines featuring an α‐tetrasubstituted stereocenter. Mechanistic studies reveal that hydrogen‐bonding interactions may greatly facilitate such unusual N‐attack reactions of imines. The utility of this protocol is highlighted by the catalytic enantioselective formal synthesis of (−)‐psychotrimine, and the construction of various fused aza‐heterocycles.

An unprecedented reductive (3 + 2) annulation of both symmetrical and unsymmetrical benzils with pyrylium salts mediated by P­(NMe2)3 is described, leading to facile and stereoselective access to the challenging cis-chalcones decorated by various substituted furyl rings under mild conditions. Rather than the extensively studied C1 synthons, the Kukhtin–Ramirez adducts derived from benzils serve as the underexplored C3 synthons in this (3 + 2) annulation with the 2,3-double bond of the 2,6-disubstituted pyrylium ions.

An unprecedented reductive [2 + 1] annulation of α-keto esters with alkynones mediated by P­(NMe2)3 is described. Although this nonmetal cyclopropenation is a nucleophilic process, attributed to the ester migration via a formal [2 + 2] cycloaddition reaction of Kukhtin–Ramirez adducts and alkynones followed by a fragmentation, cyclopropenes with an unbiased alkene scaffold are formed in good to excellent yields, thus providing a promising complementarity to electrophilic metal-catalyzed cyclopropenation.

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.

Due to high toxicity of mercury ions (Hg2+), many efforts have been devoted to realize the detection of Hg2+ with low concentration, in which to establish the relationship among the structure, electricity property, and detection activity of sensing materials is of prime importance. In this work, a field-effect transistor (FET) sensor based on a conductive Ni3(HITP)2 membrane was employed to realize Hg2+ detection. Such a Ni3(HITP)2 membrane was synthesized in situ by a one-step hydrothermal method, and the influence of the volume ratio of ammonia to water on its structure and Hg2+ detection performance was systematically investigated. It is found that with increasing the volume ratio of ammonia to water, the Ni3(HITP)2 membrane composed of flake-shaped structure becomes denser, its thickness increases from 24.1 to 114.7 nm, and the mobility of the Ni3(HITP)2 FETs increases nearly 2 orders of magnitudes. For Hg2+ detection, the Ni3(HITP)2 membrane is modified with a glutaraldehyde (GA) cross-linking agent and DNA probes. The optimized Ni3(HITP)2-GA-DNA FET-based sensor can detect Hg2+ with high specificity in a concentration range of 10 pM–100 nM. The excellent detection performance is attributed to the close contact between the Ni3(HITP)2 membrane and Si/SiO2 substrate, large surface area of the membrane, and specific bonding of Hg2+ with DNA probes modified on the membrane surface. This work will have a great significance for the application of metal–organic frameworks in electronic devices and ion detection.