Concise and efficient three-component domino [4＋ 1 ＋ 1] carbocyclization to highly substituted fluoren-9-one derivatives promoted by K2CO3 has been developed under microwave irradiation conditions. The direct bis-cy...Concise and efficient three-component domino [4＋ 1 ＋ 1] carbocyclization to highly substituted fluoren-9-one derivatives promoted by K2CO3 has been developed under microwave irradiation conditions. The direct bis-cyanation and aryl amination residing in fluoren-9-one framework were achieved in a one-pot operation. The reaction proceeds at fast rates and can be finished within 30 min, which makes workup convenient to give good to excellent chemical yields.展开更多
Nucleoside analogues show a variety of biological activities. To prepare new purine nucleoside analogues that could inhibit the proliferation of tumor cells and resist enzyrne hydrolysis, we designed and synthesized 1...Nucleoside analogues show a variety of biological activities. To prepare new purine nucleoside analogues that could inhibit the proliferation of tumor cells and resist enzyrne hydrolysis, we designed and synthesized 15 different L-5＇noraristeromycin analogues, in which thioether, sulfoxide or sulfone function was introduced to replace the 5＇-hydroxymethyl group. Their anti-tumor activities were assayed in vitro. One compound showed potent anti-tumor activity.展开更多
Achieving regioselectivity in radical cyclization reactions is of central importance,yet extremely challenging.Although Baldwin’s rules provided guidance on the addition of radical species with alkenes/alkynes,the or...Achieving regioselectivity in radical cyclization reactions is of central importance,yet extremely challenging.Although Baldwin’s rules provided guidance on the addition of radical species with alkenes/alkynes,the ortho-/ipso-selectivity of the cyclic reaction between radical species(especially alkyl and alkenyl radical)and aryl groups is still ambiguous.Herein,we develop an electrochemically enabled regioselective ortho-(4+2)/ipso-(3+2)cyclization of alkyl/alkenyl radicals with aryl groups,which provides a series of tetrahydronaphthalene and spirocarbocycle derivatives,exhibiting a broad substrate scope and functional group tolerance.Alkyl/alkenyl radicals are generated by Cp2Fe-mediated electrochemical oxidative radical addition of benzylic malonates with alkenes and alkynes.The method avoids the use of chemical oxidant/base/noble metal,the pre-functionalization of substrates,and the over-oxidation of compounds.Theoretical studies reveal that the dominant factor promoting the alkene-preferred ortho-addition is the favorable interaction energy;the alkyne-preferred ipso-addition regioselectivity is controlled by the distortion energy.Notably,this strategy is regarded as an important supplement to Baldwin’s rules for radical cyclization.展开更多
Nucleophilic chiral phosphine catalysis has been prosperous in asymmetric synthesis over the past two decades. Various tunable chiral phosphines display excellent activity and selectivity in asymmetric transformations...Nucleophilic chiral phosphine catalysis has been prosperous in asymmetric synthesis over the past two decades. Various tunable chiral phosphines display excellent activity and selectivity in asymmetric transformations including acycloaddition reactions and cycloaddition reactions. Enantiomerically enriched cyclic compounds are ubiquitous in natural products and drug molecules. These phosphinecatalyzed reactions provide effective and extensive strategies for the synthesis of a series of complex cyclic compounds as well as the synthesis of chiral compounds which could be easily transformed to carbocycles and heterocycles. This minireview summarizes recent developments in this area and highlights meaningful breakthroughs.展开更多
The hydroxyl group of carbocyclic nucleosides was inversed when the compounds were treated with Me3SiCl, KCN and a catalytic mount of NaI in DMF/CH3CN.
Enantiomerically enriched (R)-1-(2-bromocycloalkenyl)-3-buten-1-ol and its derivatives were obtained via enantioselective hydrolysis [resolution] with good enantioselectivities (E = 31 to >500) using Candida paraps...Enantiomerically enriched (R)-1-(2-bromocycloalkenyl)-3-buten-1-ol and its derivatives were obtained via enantioselective hydrolysis [resolution] with good enantioselectivities (E = 31 to >500) using Candida parapsilosis ATCC 7330. The various reaction parameters were optimized for enantioselective hydrolysis to achieve high enantiomeric excess (ee) and conversions. Among the substrates tested, (RS)-1-(2-bromocyclohex-1-en-1-yl) but-3-yn-1-yl acetate was hydrolysed by the biocatalyst in 12 h to the corresponding (R)-alcohol in 49% conversion and >99 ee. The optically pure allylic alcohol thus obtained was used as a chiral starting material for the synthesis of an enantiomerically enriched bicyclic alcohol effectively establishing achemoenzymatic route.展开更多
Comprehensive Summary.Herein,we present the first examples of asymmetric reductive 1,4-dicarbofunctionalization of 1,3-dienes and 1,5-dicarbofunctionalization of vinylcyclopropanes,which proceed under the catalysis of...Comprehensive Summary.Herein,we present the first examples of asymmetric reductive 1,4-dicarbofunctionalization of 1,3-dienes and 1,5-dicarbofunctionalization of vinylcyclopropanes,which proceed under the catalysis of a chiral nickel/bis-imidazoline complex using alkyl halides and aryl iodides or alkenyl bromides as the electrophilic coupling partners.In these highly enantioselective transformations operating in a radical relay mechanism,the C(sp3)-and C(sp2)-type carbo-moieties are respectively installed on the terminal and internal position with a newly formed olefinic unit in high E-selectivity.展开更多
Presented herein is a novel synthesis of 3-hydroxyfluorenones through the cascade reaction of aryl enaminones with benzyl substituted cyclopropanols.The formation of product is initiated by the introduction of an enon...Presented herein is a novel synthesis of 3-hydroxyfluorenones through the cascade reaction of aryl enaminones with benzyl substituted cyclopropanols.The formation of product is initiated by the introduction of an enone moiety onto aryl enaminone with cyclopropanol as a homoenolate precursor through aryl C−H bond activation,followed by intramolecular enamine Michael addition,enol Michael addition,amine elimination and aromatization-driven oxidative dehydrogenation.To our knowledge,this should be the first example for the specific synthesis of 3-hydroxyfluorenone derivatives via simultaneous formation of both indenone and phenol scaffolds through cascade C−H/C−C/C−N bond activation and three C−C bond formation.In general,this newly developed protocol features easily accessible substrates,synthetically and pharmaceutically valuable products,unique reaction pathway,good compatibility with various functional groups and ready scalability.展开更多
Comprehensive Summary A visible light photocatalytic[3+2]cycloaddition of alkynes with readily accessible organic iodides as the C3 synthon is developed herein.By merging halogen atom transfer(XAT)and hydrogen atom tr...Comprehensive Summary A visible light photocatalytic[3+2]cycloaddition of alkynes with readily accessible organic iodides as the C3 synthon is developed herein.By merging halogen atom transfer(XAT)and hydrogen atom transfer(HAT),alkyl/aryl iodides serve as a formal diradical precursor and add across C-C triple bonds to deliver a number of functionalized cyclopentanes in moderate to high yields with exceptional regio-and diastereoselectivity.A reductive radical-polar crossover mechanism,involving the cascade XAT,radical addition,1,5-HAT,polar effect-promoted 5-endo annulation,single electron transfer(SET)reduction,and protonation,may account for this unprecedented dehalogenative[3+2]cycloaddition.This work not only expands the repertoire of the traditional RATC methodology,but also provides a robust platform for the expedient assembly of cyclopentanes,a valuable structural motif in the realms of medicinal chemistry and material sciences.展开更多
Yne-allenes bearing both a C-C triple bond and an allene unit are a class of focal substrates in organic synthesis,in view of their structure diversity,.high reactivity and intermediate variety in the past years.Engag...Yne-allenes bearing both a C-C triple bond and an allene unit are a class of focal substrates in organic synthesis,in view of their structure diversity,.high reactivity and intermediate variety in the past years.Engaging yne-allenes in numerous annulation cascades provides efficient and direct accesses to elaborate functionalized polycyclic molecular architectures in a convergent manner.There are lots of types of catalytic chemical reactions such as intramolecular cyclizations,cycloisomerizations,intermolecular annulations,and bicyclizations as well as tricyclizations with the assistance of Lewis acids,Bronsted acids,bases,transition metals,and otherr c atalysts.This review provides an overview of the chemistry developed with transformations of yne-allenes by discussing their general and specific reactivities,presenting and commenting on their mechanisms as well as their applications.展开更多
A Rh(III)-catalyzed,transmetalation triggered C—H activation/annulation of 2-biphenylboronic acids with diazo compounds fromβ-keto esters or 1,3-dicarboxylates has been developed,leading to the synthesis of two kind...A Rh(III)-catalyzed,transmetalation triggered C—H activation/annulation of 2-biphenylboronic acids with diazo compounds fromβ-keto esters or 1,3-dicarboxylates has been developed,leading to the synthesis of two kinds of 9,10-phenanthrenes.Notably,a rhodacyle was synthesized by treating the rhodium catalyst with stoichiometric amounts of 2-biphenylboronic acids and pyridine,which was further verified to be active for the catalytic system.The reactions proceeded under redox-neutral and air-tolerant conditions to produce a series of all-carbon six-membered rings with high efficiency.展开更多
Although the NHC-catalyzed cyclization reactions have been well established for the synthesis of various heterocycles,the corresponding all carbon cyclization reaction for the synthesis of carbocycles is far less esta...Although the NHC-catalyzed cyclization reactions have been well established for the synthesis of various heterocycles,the corresponding all carbon cyclization reaction for the synthesis of carbocycles is far less established.In this note,the NHC-catalyzed all carbon[4+2]cyclocondensation of α,β-unsaturated acyl chlorides and 3-alkenyloxindoles was developed to give the corresponding spirocarbocyclic oxindoles in good yield with good to high diastereoselectivities.展开更多
Molecular scaffolds endowed with all-carbon quaternary stereocenter are ubiquitous in natural products and significant bioactive molecules.However,efficient construction of this type of structure units is full of chal...Molecular scaffolds endowed with all-carbon quaternary stereocenter are ubiquitous in natural products and significant bioactive molecules.However,efficient construction of this type of structure units is full of challenge due to their congested chemical envi-ronment.Herein,we report a new gold(Ⅰ)self-relay catalysis merging[3,3]-sigmatropic rearrangement/Nazarov cyclization with al-lylic alkylation starting from 1,3-enyne acetates and allylic alcohols,producing a wide range of synthetically important allyl cyclo-pentenones with an all-carbon quaternary stereocenter in good yields under mild conditions.This protocol demonstrates the precise control of regioselectivity,high functional group tolerance of substrates and the low loading of gold catalyst without inert atmos-phere protection,providing a catalytic and efficient entry to all-carbon quaternary stereocenters.展开更多
文摘Concise and efficient three-component domino [4＋ 1 ＋ 1] carbocyclization to highly substituted fluoren-9-one derivatives promoted by K2CO3 has been developed under microwave irradiation conditions. The direct bis-cyanation and aryl amination residing in fluoren-9-one framework were achieved in a one-pot operation. The reaction proceeds at fast rates and can be finished within 30 min, which makes workup convenient to give good to excellent chemical yields.
基金National Natural Science Foundation of China(Grant No.20672010)
文摘Nucleoside analogues show a variety of biological activities. To prepare new purine nucleoside analogues that could inhibit the proliferation of tumor cells and resist enzyrne hydrolysis, we designed and synthesized 15 different L-5＇noraristeromycin analogues, in which thioether, sulfoxide or sulfone function was introduced to replace the 5＇-hydroxymethyl group. Their anti-tumor activities were assayed in vitro. One compound showed potent anti-tumor activity.
文摘Achieving regioselectivity in radical cyclization reactions is of central importance,yet extremely challenging.Although Baldwin’s rules provided guidance on the addition of radical species with alkenes/alkynes,the ortho-/ipso-selectivity of the cyclic reaction between radical species(especially alkyl and alkenyl radical)and aryl groups is still ambiguous.Herein,we develop an electrochemically enabled regioselective ortho-(4+2)/ipso-(3+2)cyclization of alkyl/alkenyl radicals with aryl groups,which provides a series of tetrahydronaphthalene and spirocarbocycle derivatives,exhibiting a broad substrate scope and functional group tolerance.Alkyl/alkenyl radicals are generated by Cp2Fe-mediated electrochemical oxidative radical addition of benzylic malonates with alkenes and alkynes.The method avoids the use of chemical oxidant/base/noble metal,the pre-functionalization of substrates,and the over-oxidation of compounds.Theoretical studies reveal that the dominant factor promoting the alkene-preferred ortho-addition is the favorable interaction energy;the alkyne-preferred ipso-addition regioselectivity is controlled by the distortion energy.Notably,this strategy is regarded as an important supplement to Baldwin’s rules for radical cyclization.
基金financial support from the National Basic Research Program of China(973 Project,No.2015CB856603)the National Natural Science Foundation of China(Nos.20472096,21372241,21361140350,20672127,21421091,21372250,21121062,21302203,20732008 and 21572052)
文摘Nucleophilic chiral phosphine catalysis has been prosperous in asymmetric synthesis over the past two decades. Various tunable chiral phosphines display excellent activity and selectivity in asymmetric transformations including acycloaddition reactions and cycloaddition reactions. Enantiomerically enriched cyclic compounds are ubiquitous in natural products and drug molecules. These phosphinecatalyzed reactions provide effective and extensive strategies for the synthesis of a series of complex cyclic compounds as well as the synthesis of chiral compounds which could be easily transformed to carbocycles and heterocycles. This minireview summarizes recent developments in this area and highlights meaningful breakthroughs.
文摘The hydroxyl group of carbocyclic nucleosides was inversed when the compounds were treated with Me3SiCl, KCN and a catalytic mount of NaI in DMF/CH3CN.
文摘Enantiomerically enriched (R)-1-(2-bromocycloalkenyl)-3-buten-1-ol and its derivatives were obtained via enantioselective hydrolysis [resolution] with good enantioselectivities (E = 31 to >500) using Candida parapsilosis ATCC 7330. The various reaction parameters were optimized for enantioselective hydrolysis to achieve high enantiomeric excess (ee) and conversions. Among the substrates tested, (RS)-1-(2-bromocyclohex-1-en-1-yl) but-3-yn-1-yl acetate was hydrolysed by the biocatalyst in 12 h to the corresponding (R)-alcohol in 49% conversion and >99 ee. The optically pure allylic alcohol thus obtained was used as a chiral starting material for the synthesis of an enantiomerically enriched bicyclic alcohol effectively establishing achemoenzymatic route.
基金supported by the National Natural Science Foundation of China(22271267,21772183,22471256).
文摘Comprehensive Summary.Herein,we present the first examples of asymmetric reductive 1,4-dicarbofunctionalization of 1,3-dienes and 1,5-dicarbofunctionalization of vinylcyclopropanes,which proceed under the catalysis of a chiral nickel/bis-imidazoline complex using alkyl halides and aryl iodides or alkenyl bromides as the electrophilic coupling partners.In these highly enantioselective transformations operating in a radical relay mechanism,the C(sp3)-and C(sp2)-type carbo-moieties are respectively installed on the terminal and internal position with a newly formed olefinic unit in high E-selectivity.
基金We are grateful to Postdoctoral Research Grant in Henan Province(HN2022041)Key Research Projects of Universities in Henan Province(24A150018)NMPA Key Laboratory for Research and Evaluation of Innovative Drug,Henan Key Laboratory of Organic Functional Molecules and Drug Innovation,and 111 Project(D17007)for financial support.
文摘Presented herein is a novel synthesis of 3-hydroxyfluorenones through the cascade reaction of aryl enaminones with benzyl substituted cyclopropanols.The formation of product is initiated by the introduction of an enone moiety onto aryl enaminone with cyclopropanol as a homoenolate precursor through aryl C−H bond activation,followed by intramolecular enamine Michael addition,enol Michael addition,amine elimination and aromatization-driven oxidative dehydrogenation.To our knowledge,this should be the first example for the specific synthesis of 3-hydroxyfluorenone derivatives via simultaneous formation of both indenone and phenol scaffolds through cascade C−H/C−C/C−N bond activation and three C−C bond formation.In general,this newly developed protocol features easily accessible substrates,synthetically and pharmaceutically valuable products,unique reaction pathway,good compatibility with various functional groups and ready scalability.
基金supported by the Natural Science Foundation of Zhejiang Province(LZ20B020001 and LY23B020004)the Ten Thousand Talents Plan of Zhejiang Province(2020R52021)+1 种基金the Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang Province(2022R01007)the National Natural Science Foundation of China(22371262,22071218,and 22203076).
文摘Comprehensive Summary A visible light photocatalytic[3+2]cycloaddition of alkynes with readily accessible organic iodides as the C3 synthon is developed herein.By merging halogen atom transfer(XAT)and hydrogen atom transfer(HAT),alkyl/aryl iodides serve as a formal diradical precursor and add across C-C triple bonds to deliver a number of functionalized cyclopentanes in moderate to high yields with exceptional regio-and diastereoselectivity.A reductive radical-polar crossover mechanism,involving the cascade XAT,radical addition,1,5-HAT,polar effect-promoted 5-endo annulation,single electron transfer(SET)reduction,and protonation,may account for this unprecedented dehalogenative[3+2]cycloaddition.This work not only expands the repertoire of the traditional RATC methodology,but also provides a robust platform for the expedient assembly of cyclopentanes,a valuable structural motif in the realms of medicinal chemistry and material sciences.
基金We are grateful for financial support from the National Natural ScienceFoundation of China(Nos.21871112 and 21971090).
文摘Yne-allenes bearing both a C-C triple bond and an allene unit are a class of focal substrates in organic synthesis,in view of their structure diversity,.high reactivity and intermediate variety in the past years.Engaging yne-allenes in numerous annulation cascades provides efficient and direct accesses to elaborate functionalized polycyclic molecular architectures in a convergent manner.There are lots of types of catalytic chemical reactions such as intramolecular cyclizations,cycloisomerizations,intermolecular annulations,and bicyclizations as well as tricyclizations with the assistance of Lewis acids,Bronsted acids,bases,transition metals,and otherr c atalysts.This review provides an overview of the chemistry developed with transformations of yne-allenes by discussing their general and specific reactivities,presenting and commenting on their mechanisms as well as their applications.
基金the financial support for this work from the National Key R&D Program of China(2021YFC0864700)the NSFC(Nos.21801066,U1804283 and 82130103)+2 种基金the Central Plains Scholars and Scientists Studio Fund(2018002)the project funded by the Natural Science Foundation of Henan Province(222300420056,222300420204)the China Postdoctoral Science Foundation(2020M682307,2021T140183).
文摘A Rh(III)-catalyzed,transmetalation triggered C—H activation/annulation of 2-biphenylboronic acids with diazo compounds fromβ-keto esters or 1,3-dicarboxylates has been developed,leading to the synthesis of two kinds of 9,10-phenanthrenes.Notably,a rhodacyle was synthesized by treating the rhodium catalyst with stoichiometric amounts of 2-biphenylboronic acids and pyridine,which was further verified to be active for the catalytic system.The reactions proceeded under redox-neutral and air-tolerant conditions to produce a series of all-carbon six-membered rings with high efficiency.
基金Financial support from National Natural Science Foundation of China(No.21272237)the Ministry of Science and Technology of China(No.2011CB808600)the Chinese Academy of Sciences is gratefully acknowledged.
文摘Although the NHC-catalyzed cyclization reactions have been well established for the synthesis of various heterocycles,the corresponding all carbon cyclization reaction for the synthesis of carbocycles is far less established.In this note,the NHC-catalyzed all carbon[4+2]cyclocondensation of α,β-unsaturated acyl chlorides and 3-alkenyloxindoles was developed to give the corresponding spirocarbocyclic oxindoles in good yield with good to high diastereoselectivities.
基金We are grateful for financial support from the National Natural Science Foundation of China(Nos.21871112 and 21971090)the Science and Technology of Xuzhou(KC21022)。
文摘Molecular scaffolds endowed with all-carbon quaternary stereocenter are ubiquitous in natural products and significant bioactive molecules.However,efficient construction of this type of structure units is full of challenge due to their congested chemical envi-ronment.Herein,we report a new gold(Ⅰ)self-relay catalysis merging[3,3]-sigmatropic rearrangement/Nazarov cyclization with al-lylic alkylation starting from 1,3-enyne acetates and allylic alcohols,producing a wide range of synthetically important allyl cyclo-pentenones with an all-carbon quaternary stereocenter in good yields under mild conditions.This protocol demonstrates the precise control of regioselectivity,high functional group tolerance of substrates and the low loading of gold catalyst without inert atmos-phere protection,providing a catalytic and efficient entry to all-carbon quaternary stereocenters.
