查看更多>>摘要：Compared to well-established 1,5-HAT of N-centered radicals,the synthetic applications of 1,2-HAT process were scarce due to the high barrier and constrained three-membered transition state.Here,we have developed a novel C(sp3)-H gem-difluoroallylation via a base assisted formal 1,2-HAT of amidyl radicals with the reductive quenching cycle of photocatalyst.This transformation enables the efficient formation of a-aminoalkyl radicals via 1,2-HAT and showcases good functional group tolerance.Our preliminary mechanistic experiments,along with Density Functional Theory(DFT)calculations demonstrate the feasibility of 1,2-HAT of amidyl radicals,espe-cially when assisted by a base.Furthermore,our method also succeeds in the Giese addition of electron-deficient alkenes as well as styrene.
查看更多>>摘要：Although it offers a direct route to access synthetically valuable a-chiral primary amines,asymmetric transfer hydrogenation of NH imines has been rarely studied,due in large part to the inaccessibility and instability of NH imines.Herein,we report a Rh-catalyzed asymmetric transfer hydrogenation of a kind of novel and stable NH imines which are prepared via condensation of easily available sulfonylated 2'-aminoacetophenones with NH3 in methanol.With this method,enantioenriched chiral 2-(1-aminoalkyl)anilines,which are privileged pharmacore groups,have been synthesized with good functional group compatibility,and with up to 99％ee.A gram-scale reaction using 0.2 mol％of catalyst has been successfully performed to highlight the practicality.Furthermore,the products can be derivatized into enantiopure bioactive molecules as well as chiral tridentate ligands for metal catalysis.
查看更多>>摘要：In this paper,the difunctionalizative perfluoroalkyloximation of alkenes has been developed for the first time.This photochemical method allows for the synthesis of various perfluoroalkyl ethanone oximes with excellent regioselectivity and good functional group tolerance.Our method employs the most common perfluoroalkyl source,perfluoroalkyl iodides,as Rf reagents.Besides long-chain perfluoroalkyl groups,this approach could be extended to incorporating additional groups,including trifluoromethyl,difluoromethyl,sulfonyl,and malonate,selectively into olefins,resulting in a range of β-substituted ethanone oximes.Notably,the potential of this method in the Fukuyama indole synthesis,generating novel 2-perfluoroalkylated 3-(α-oximidobenzyl)indoles via a radical cascade mechanism with 2-vinylphenylacryloyl isocyanate as the radical acceptor,presents a compelling avenue for drug synthesis.The proto-col is efficient,scalable,and useful for late-stage modification of bioactive molecules.
查看更多>>摘要：Allenes,served as highly sought-after building blocks,are an indispensable component of synthetic chemistry.Their utility in modu-lating the chemical,physical,and pharmaceutical properties of organic compounds make allenes a desirable choice in various applica-tions.Here,we report a facile method for the atom-economical synthesis of propargyl allenylamines via an underdeveloped[2,3]-sigmatropic rearrangement.Our strategy employs easily accessible propargylamines as starting materials,which are first con-verted into propargyl ammonium salts,followed by a base-promoted[2,3]-sigmatropic rearrangement.This one-pot,two-step reac-tion proceeds in the absence of transition metals,displays a very broad scope,and does not require the introduction of the elec-tron-withdrawing group into the starting materials.
查看更多>>摘要：Unsymmetrical diarylamines are crucial components in many pharmaceuticals and functional materials.In this study,we introduce an efficient Chan-Lam cross-coupling method that utilizes phenylboronic acids and aryl azides as coupling agents in a redox-neutral envi-ronment,enabled by a synergistic nickel/photoredox catalytic system.This approach leverages a proton-coupled electron transfer mechanism to bypass the typical nitrene pathway associated with aryl azides,which is prone to intramolecular rearrangement,C-H amination,and reductive hydrogenation.Notably,our method exhibits broad compatibility with a variety of functional groups,includ-ing those derived from pharmaceuticals,demonstrating its versatile potential in organic synthesis and drug modification.
查看更多>>摘要：A visible-light-induced photoredox-catalyzed regioselective and stereoselective C(sp2)-H amination of enamides with bench-stable and easily accessible N-aminopyridium salts is developed,affording synthetically and biologically prominent vicinal 1,2-diamine scaffolds with broad substrate scope and excellent functional group compatibility.The transformation proceeded through a radical pathway in-volving the Giese addition of the relatively electrophilic N-centered sulfonamidyl radical species to nucleophilic β-olefinic position of enamides followed by the ensuing single electron oxidation and β-H elimination,delivering geometrically-defined Z-configuredβ-sulfonamidylated enamides.The operational simplicity,environmental friendliness and cost efficiency of this methodology allowed it to pave a new avenue to enrich the arsenal of synthetically crucial functionalized enamides and their related derivatives.
查看更多>>摘要：Herein,we report rhodium catalyzed N-arylation via addition of arylboronic acids to electron-deficient α-iminoesters which can be prepared in high efficiency by using easily accessible β-carbonyl esters.The reaction is highly regiospecific to achieve the N-aryl addi-tion efficiently with up to 99％yield under mild conditions.The corresponding product can be further efficiently converted into indoles and a series of other important building blocks.
查看更多>>摘要：CO2 is an abundant,nontoxic,and renewable C1 feedstock in synthetic chemistry.Direct carboxylation of readily available olefins in-corporating CO2 is regarded as a promising strategy to access high value-added carboxylic acids as well as CO2 fixation.However,due to the thermodynamic stability and kinetic inertness of CO2 and the difficulty in controlling the regioselectivity,the carboxylation of olefins with CO2 still remains challenging.Radical-type functionalization with olefins represented a powerful protocol and enabled the development of novel transformations in this realm.More recently,the advance of new technology,such as photoredox catalysis and the renaissance of electrochemistry in organic synthesis,offered access to unique chemical reactivities of radical precursors and pro-vided new solutions to the functionalization of olefins.This review presents the recent advances in the radical-type carboxylation of olefins,which has mainly been achieved through photocatalysis and electrocatalysis in the last decade.In this article,we provide a comprehensive introduction of the progress,summarize the advantages and limitations of current research,and discuss the potential outlook for further development.
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