CuI/8-Hydroxyquinalidine Promoted N-Arylation of Indole and Azoles

A machine-learning tool to predict substrate-adaptive conditions for Pd-catalyzed C-N couplings

Machine-learning methods have great potential to accelerate the identification of reaction conditions for chemical transformations. A tool that gives substrate-adaptive conditions for palladium (Pd)-catalyzed carbon-nitrogen (C-N) couplings is presented. The design and construction of this tool required the generation of an experimental dataset that explores a diverse network of reactant pairings across a set of reaction conditions. A large scope of C-N couplings was actively learned by neural network models by using a systematic process to design experiments. The models showed good performance in experimental validation: Ten products were isolated in more than 85% yield from a range of couplings with out-of-sample reactants designed to challenge the models. Importantly, the developed workflow continually improves the prediction capability of the tool as the corpus of data grows.

Copper-catalyzed N-arylation of indoles

Abstract:

Over the past decades, the N-arylation of indoles has gained an inevitable role in the fields of material science, pharmaceuticals, and agrochemical industries. They are the basic core skeleton of many natural products. Their synthesis by Ullmann-type C–N coupling reaction of indole derivatives with aryl halides through various catalytic protocols is well explored. Transition metal catalysis was the best method for synthesizing 1-aryl indoles, and copper catalysis is the leading among them. This review comprehends the recent developments in the copper-catalyzed C–N cross-coupling of indoles with aryl halides from 2010 to 2022.

Recent Progress Concerning the N-Arylation of Indoles

This review summarizes the current state-of-the-art procedures in terms of the preparation of N-arylindoles. After a short introduction, the transition-metal-free procedures available for the N-arylation of indoles are briefly discussed. Then, the nickel-catalyzed and palladium-catalyzed N-arylation of indoles are both discussed. In the next section, copper-catalyzed procedures for the N-arylation of indoles are described. The final section focuses on recent findings in the field of biologically active N-arylindoles.

A convenient eco-friendly system for the synthesis of 5-sulfenyl tetrazole derivatives of indoles and pyrroles employing CeCl3·7H2O in PEG-400

The use of CeCl₃·7H₂O in PEG-400 for the convenient synthesis of 5-sulfenyl tetrazoles derived from indoles and pyrroles, is reported. The scope and limitations of the transformation were also studied.