Although,great achievements have been made in the synthesis of heterocycles using radical addition/cyclization strategy,developing versatile alkyl radical precursors,especially the non-stabilized long chain alkyl radicals for this strategy still remains a huge challenge.Herein,we report an efficient annulation cascade reaction between cyclosulfonium salts and alkenes for the synthesis of sulfur-containing N-heterocycles by visible light/copper catalysis under mild conditions.The C—S bond cleavage/radical cascade reaction delivers a variety of corresponding N-heterocycles containing aryl alkyl thioether motifs with good functional group tolerance.Significantly,the current system could be used for the late-stage functionalization of complex bioactive molecules.
Jie MaXufeng LiYuqing ChenYongjia ShiXiuyan SongJian LvDaoshan Yang
The production of high-valued organonitrogen chemicals,especially N-heterocycles,requires artificial N_(2)fixation accompanied by the consumption of fossil resources.To avoid the use of these energy-and resource-intensive processes,we develop a sustainable strategy to convert nitrogen-rich animal biomass into N-heterocycles through a thermochemical conversion process(TCP)under atmospheric pressure.A high percentage of N-heterocycles(87.51%)were obtained after the TCP of bovine skin due to the abundance of nitrogen-containing amino acids(e.g.,glycine,proline,and L-hydroxyproline).Animal biomass with more diverse amino acid composition(e.g.,muscles)yielded higher concentrations of amines/amides and nitriles after TCP.In addition,by introducing catalysts(KOH for pyrrole and Al_(2)O_(3)for cyclo-Gly-Pro)to TCP,the production quantities of pyrrole and cyclo-Gly-Pro increased to 30.79 mg g^(-1)and 38.88 mg g^(-1),respectively.This approach can be used to convert the significant animal biomass waste generated annually from animal culls into valued organonitrogen chemicals while circumventing NH3-dependent and petro-chemical-dependent synthesis routes.
Yang TangXiao XiaoChaojun ZhangXiaoling WangJunling GuoXuepin Liao
Fused polycyclic N-heterocycles are very important scaffolds in biomedicinal chemistry and materials science.Intramolecular alkyne hydroamination is a powerful method for the construction of N-heterocycles.In the last two decades,copper-catalyzed domino reactions based on intramolecular alkyne hydroamination has emerged as a robust strategy for assembling various fused polycyclic N-heterocycles.Great progress has been achieved in this area.This short review covers the advances made in copper-catalyzed domino synthesis of fused polycyclic N-heterocycles based on the strategy from 2008 to 2023,and will hopefully serve as an inspiration towards the exploration of new copper-catalyzed versions of the transformation.The domino transformations are introduced and discussed from five aspects according to the different key processes involved in these reactions.
The aqueous zinc-organic battery is a promising candidate for large-scale energy storage.However,the rational design of advanced organic cathodes with high capacity,long lifespan,and high rate capability remains a big challenge.Herein,we propose that extending theπ-conjugation by N-heterocycles can provide more active sites,lead to insolubility,and facilitate charge transfer,thus boosting the overall electrochemical performance of organic electrodes.Based on this concept,a novel organic compound,dipyrido[3ʹ,2ʹ:5,6;2″,3″:7,8]quinoxalino[2,3-i]dipyrido[3,2-a:2ʹ,3ʹ-c]phenazine-10,21-dione(DQDPD),has been rationally designed and evaluated as the cathode for aqueous zinc batteries.Excitingly,DQDPD shows a record high capacity(509 mAh g^(−1) at 0.1 A g^(−1),corresponding to a record-breaking energy density of 348 Wh kg^(−1)),excellent cycling stability(92%capacity retention after 7500 cycles at 10 A g^(−1)),and fast-charging capability(161 mAh g^(−1) at 20 A g^(−1)).Our work offers new ideas in the molecular engineering of organic electrodes for high-performance rechargeable batteries.
Synthetic N-heterocyclic compounds,such as quinoxalines,have shown a crucial role in pharmaceutical as well as food and dye industries.However,the traditional synthesis toward N-heterocycles relies on multistep energy and costintensive non-sustainable processes.Here,we report a facile approach that allows one-step conversion of biomass-derived carbohydrates to valuable quinoxalines in the presence of aryl-1,2-diamines in water without any harmful metal catalysts/organic solvents via spontaneously engineering involved cascade reactions under hydrothermal conditions.Aryl-1,2-diamines are revealed as the key to propel this transformation through boosting carbohydrate fragmentation into small 1,2-dicarbonyl intermediates and subsequently trapping them for constituting stable quinoxaline scaffolds therefore avoiding a myriad of undesired side reactions.The tunability of product selectivity can be also achievable by adjusting the basicity of the reaction environment.Both batch and continuous-flow integrated processes were verified for production of quinoxalines in an exceptionally eco-benign manner(E-factor<1),showing superior sustainability and economic viability.
By exploiting the combined use of a heterogeneous recyclable palladium(II)-bis(N-heterocyclic carbene)catalyst and cyclopentyl methyl ether(CPME)as a convenient recoverable safer reaction medium,an effective wasteminimized approach has been developed for the intramolecular Pd-catalyzed C(sp3)-H activation of methyl pyrrole derivatives.This synthetic tools has allowed to access condensed N-heterocycles generally endowed with biological activities and representatively are the core motif of complex molecules such as Mitomycines and Tylophorines.The heterogeneous catalytic system could be recovered and reused up to representative five runs without any loss in efficiency.The target products(19 examples)have been obtained selectively and with excellent isolated yields up to 93%.The approach leads to the definition of a protocol with a very good E-factor(21)which is much lower(up to 98%)than those of comparable literature examples.Other green metrics have been calculated and the data collected demonstrate that our newly developed protocol is very promising in terms of its environmental impact profile.
Chiral benzo-fused N-heterocycles are frequently found innatural and synthetic products.However,their synthesis usually suffers from different limitations such as difficulty in accessing appropriate starting materials and unsatisfactory stereoselectivities.In this work,an unprecedented chiral sulfide-catalyzed enantioselective Friedel-Crafts-type electrophilic chlorination is shown to construct various 3,4-functionalized tetrahydroquinolines with excellent enantio-and diastereoselectivities from readily available aniline derivatives.Interestingly,employing N-allyl 1-naphthanilides as substrates,divergent reactions via chlorocarbocyclization and dearomatization occurred to afford two chiral polycyclic benzo-fused N-heterocycles.The system that we developed extends the scope of asymmetric chlorination to general substrateswithout the need of a N-H group,and significantly promotes the synthesis of enantioenriched benzo-fused N-heterocycles.
The development of an efficient and sustainable synthetic route for formaldehyde production from renewable feedstock,especially in combination with a subsequent transformation to straightforwardly construct valuable chemicals,is highly desirable.Herein,we report a novel manganese-catalyzed dehydrogenative cyclization of methanol as a formaldehyde surrogate with a variety of dinucleophiles for facile synthesis of N-heterocycles.The in situ generated formaldehyde via catalytic methanol dehydrogenation can be selectively trapped by diverse dinucleophiles to avoid several possible side reactions.The utilty of this transformation is further highlighted by its successful appliation to the synthesis of 13C-labeled N-heterocycles using 13CH_(3)OH as a readily accessible 13C-isotope reagent.
