Reductive N-Formylation of Nitroarenes Mediated by Rongalite

Herein, we disclose a straightforward approach to access transition-metal-free reductive N-formylation of nitroarenes. This reaction integrates the dual role of rongalite, which acts as a reductant and a C1 building block concurrently. This provides an alternative method for the synthesis of N-aryl formamides from nitroarenes, including the construction of a C-N bond. The utility of this protocol was demonstrated by scale-up synthesis and late-stage functionalizations of complex molecules.

N-Formylation of amines utilizing CO2 by a heterogeneous metal–organic framework supported single-site cobalt catalyst

Single-site cobalt-hydride supported on oxo-nodes of a porous aluminium metal–organic framework is a chemoselective and reusable catalyst for N-formylation of amines using CO2.

Recent Advances on Heteroatom-Doped Porous Carbon/Metal Materials: Fascinating Heterogeneous Catalysts for Organic Transformations

Design and preparation of low-cost, effective, and novel catalysts are important topics in the field of heterogeneous catalysis from academic and industrial perspectives. Recently, heteroatom-doped porous carbon/metal materials have received significant attention as promising catalysts in divergent organic reactions. Incorporation of heteroatom into the carbon framework can tailor the properties of carbon, providing suitable interaction between support and metal, resulting in superior catalytic performance compared with those of traditional pure carbon/metal catalytic systems. In this review, we try to underscore the recent advances in the design, preparation, and application of heteroatom-doped porous carbon/metal catalysts towards various organic transformations.

Facile access to N-formyl imide as an N-formylating agent for the direct synthesis of N-formamides, benzimidazoles and quinazolinones

N-Formamide synthesis using N-formyl imide with primary and secondary amines with catalytic amounts of p-toluenesulfonic acid monohydrate (TsOH·H₂O) is described. This reaction is performed in water without the use of surfactants. Moreover, N-formyl imide is efficiently synthesized using acylamidines with TsOH·H₂O in water. In addition, N-formyl imide was successfully used as a carbonyl source in the synthesis of benzimidazole and quinazolinone derivatives. Notable features of N-formylation of amines by using N-formyl imide include operational simplicity, oxidant- and metal-free conditions, structurally diverse products, and easy applicability to gram-scale operation.

Copper Promoted Aerobic Oxidative C(sp3)-C(sp3) Bond Cleavage of N-(2-(Pyridin-2-yl)-ethyl)anilines

A strategy of aerobic oxidative C(sp³)-C(sp³) bond cleavage of N-ethylaniline derivatives bearing azaarenes for the synthesis of N-aryl formamides has been developed. This approach was carried out smoothly with the CuI/TEMPO/air system to give N-aryl formamides in yields of 50-90%. With this methodology, a mutagenically active compound was constructed in 90% yield. Moreover, the reaction also provided a one-pot synthetic tool for accessing a promoter of hematopoietic stem cells by difunctionalization in 61% yield.

Synergistic catalysis on Fe-N x sites and Fe nanoparticles for efficient synthesis of quinolines and quinazolinones via oxidative coupling of amines and aldehydes

In this paper, we developed a reusable heterogeneous non-precious iron nanocomposite comprising metallic Fe-Fe3C nanoparticles and Fe-N x sites on N-doped porous carbon, which allows for highly efficient synthesis of quinolines and quinazolinones via oxidative coupling of amines and aldehydes using H2O2 as the oxidant in aqueous solution under mild conditions. A set of quinazolines and quinazolinones were synthesized in high yields with a broad substrate scope and good tolerance of functional groups. Characterization and control experiments disclose that a synergistic effect between the metallic Fe nanoparticles and built-in Fe-N x sites is primarily responsible for the outstanding catalytic performance. Furthermore, the iron nanocomposite could be readily recovered for successive use without appreciable loss in catalytic activity and selectivity. This work provides an expedient and sustainable method to access pharmaceutically relevant N-heterocycles.

Hydrogenation of Functionalized Nitroarenes Catalyzed by Single-Phase Pyrite FeS2 Nanoparticles on N,S-Codoped Porous Carbon

Catalytic hydrogenation of nitroarenes is an industrially very important and environmentally friendly process for the production of anilines; however, highly chemoselective reduction of nitroarenes decorated with one or more reducible groups in a nitroarene molecule remains a challenge. Herein, a novel hybrid non-noble iron-based nanocatalyst (named as FeS₂ /NSC) was developed, which was prepared from biomass as C and N source together with inexpensive Fe(NO₃ )₃ as Fe source through high-temperature pyrolysis in a straightforward and cost-effective procedure. Comprehensive characterization revealed that single-phase pyrite FeS₂ nanoparticles with precisely defined composition and uniform size were homogeneously dispersed on N,S-codoped porous carbon with large specific surface area, hierarchical porous channels, and high pore volume. The resultant catalyst FeS₂ /NSC demonstrated good catalytic activity for hydrogenation of functionalized nitroarenes with good tolerance of various functional groups in water as a sustainable and green solvent. Compared with bulk pyrite FeS₂ and other non-noble metal-based heterogeneous catalysts reported in the literature, a remarkably enhanced activity was observed under mild reaction conditions. More importantly, FeS₂ /NSC displayed exclusive chemoselectivity for the reduction of nitro groups for nitroarenes bearing varying readily reducible groups.

Metal Nanoparticles Supported on Biomass-Derived Hierarchical Porous Heteroatom-Doped Carbon from Bamboo Shoots: Design, Synthesis and Applications

Heteroatom-doped porous carbon derived from biomass have recently received increasing attention due to their unique properties such as high electrical conductivity, large specific surface area, high porosity, and easy availability, which are appealing materials for versatile applications in catalysis, energy, separation and adsorption, and life sciences as well. On the basis of our previous work in this field, we summarized in this account our recent progress on design, synthesis of metal (e. g., Pd, Co) nanoparticles supported heteroatom-doped hierarchical porous carbon material derived from bamboo shoots and their applications for important organic transformations, including chemoselective semihydrogenation of alkynes, hydrosilylation of alkynes, cascade synthesis of benzofurans from terminal alkynes and iodophenols, selective hydrogenation of functionalized nitroarenes to form anilines, imines, and formamides. Finally, the current state and future challenges in this field are discussed. We hope this account could shed light on the rational design of novel non-noble metal based heterogeneous catalysts derived from biomass for efficient and sustainable organic transformations.