The bacterium Xanthomonas oryzae pv.Oryzae(Xoo)causes blight in rice worldwide,resulting in signifi-cant crop loss.However,no gene underlying a quantitative trait locus(QTL)for resistance against Xoo has been cloned y...The bacterium Xanthomonas oryzae pv.Oryzae(Xoo)causes blight in rice worldwide,resulting in signifi-cant crop loss.However,no gene underlying a quantitative trait locus(QTL)for resistance against Xoo has been cloned yet.Here,we report the map-based cloning of a QTL,in which the NBS8R gene confers quantitative resistance to Xoo.NBS8R encodes an NB-ARC protein,which is involved in pathogen/microbe-associated molecular pattern-triggered immunity and whose expression is regulated by non-TAL effector XopQ-inducible Osa-miR1876 through DNA methylation.Sequence analysis of NBS8R in wild rice species and rice cultivars suggests that the Osa-miR1876 binding sites in the 5'UTR of NBS8R are inserted by chance and have undergone variations with Osa-miR1876 throughout evolution.The inter-action between NBS8R and XopQ-inducible Osa-miR1876 is partially in keeping with the zigzag model,revealing that quantitative genes may also follow this model to control the innate immune response or basal disease resistance,and may prove valuable in utilizing the existing landraces that harbor the NBS8R gene but with no Osa-miR1876 binding site in rice breeding for bacterial blight resistance.展开更多
Silylated fluoroalkenes are important synthetic intermediates with complementary reactivity,which play a key role in the construction of natural products,pharmaceuticals,and manmade materials.Converting the normally h...Silylated fluoroalkenes are important synthetic intermediates with complementary reactivity,which play a key role in the construction of natural products,pharmaceuticals,and manmade materials.Converting the normally highly stable fiuoroalkenes into silylated fluoroalkenes by selective defluorosilylation is a challenging task.Herein,we report a simple,inexpensive and robust defluorosilylation of a variety of fluoroalkenes with silylboronates in the presence of alkoxy base to directly synthesize various silylated fluoroalkenes.The protocol features mild and safe reaction conditions that avoid a catalyst,a transition metal,a ligand,and high reaction temperature and tolerates a wide scope of fluoroalkene substrates without compromising the efficiency.Density functional theory calculations show that transient silyl anion complex undergoes an SN2,or SNv substitution,which is responsible for this base-mediated defluorosilylation.展开更多
The first Chinese Chemical Letters(CCL)Organic Chemistry Forum was held in Xiamen of Fujian in Jan.2018,followed by the successful events in Zhengzhou of Henan in Dec.2019 and Linzhi of Tibet in July 2021.The series o...The first Chinese Chemical Letters(CCL)Organic Chemistry Forum was held in Xiamen of Fujian in Jan.2018,followed by the successful events in Zhengzhou of Henan in Dec.2019 and Linzhi of Tibet in July 2021.The series of forums aim to build a high-level organic chemistry academic exchange platform for(Chinese)youthful organic chemists,fully showcase their latest fron-tier achievements,and enhance the international level of organic chemistry in China.At the same time,the convening of the series of forums has also played a positive role in promoting the devel-opment of China’s scientific journal publishing,accelerating the re-alization of the strategic goal of building a world-class journal.展开更多
Monofluoroalkenes are important and versatile privileged components in pharmacologically relevant molecules.Here,we report a method for the selective construction of these compounds in a diversity-oriented fashion thr...Monofluoroalkenes are important and versatile privileged components in pharmacologically relevant molecules.Here,we report a method for the selective construction of these compounds in a diversity-oriented fashion through regiodivergent cross-coupling of gem-difluorocyclopropanes with allylboronates by employing a palladium catalyst with two different ligands,in which gem-difluorocyclopropanes were used as allyl electrophiles by C—C and C—F bond activation.In the presence of 2-biphenylyl(diphenyl)phosphine as ligand,the linear-selective allyl–allyl bond formation is highly obtained,while utilizing the sterically hindered BrettPhos(dicyclohexyl[3,6-dimethoxy-2',4',6'-tris(1-methylethyl)[1,1'-biphenyl]-2-yl]phosphine)as the ligand favors the generation of the branched-selective product.Experimental and computational studies investigated the key steps of the cross-coupling reactions,revealing the origin of the ligand-controlled regiodivergence.展开更多
A nickel-catalyzed reductive cross-coupling reactions between polyfluoroarenes and alkyl electrophiles is reported to access substituted fluoroarenes through chelation-assisted C–F activation.Diverse primary and seco...A nickel-catalyzed reductive cross-coupling reactions between polyfluoroarenes and alkyl electrophiles is reported to access substituted fluoroarenes through chelation-assisted C–F activation.Diverse primary and secondary alkyl(pseudo)halides can be employed to couple with polyfluoroarenes,showing excellent regioselectivity.Furthermore,the nickel-catalyzed asymmetric cross-coupling of polyfluoroarenes with racemic alkyl halides is preliminarily explored.In addition,the practicability of the title transformation is also demonstrated by total synthesis of losmapimod and an analog as key steps.The developed method exhibits many advantages,including economic catalytic systems,commercially available alkyl electrophiles,and lack of sensitive organometallic reagents.展开更多
A novel protocol for palladium-catalyzed fluoroarylation of 1,1-difluoroallenes was described here.The reaction proceeded smoothly under mild condition and various trifluoromethylated alkenes were obtained in moderate...A novel protocol for palladium-catalyzed fluoroarylation of 1,1-difluoroallenes was described here.The reaction proceeded smoothly under mild condition and various trifluoromethylated alkenes were obtained in moderate yields with excellent E selectivity.The mechanism involving a vital trifluoromethylated vinyl silver intermediate,which generated through the F-nucleophilic addition to 1,1-difluoroallenes,has been proposed.展开更多
Transition metal-catalyzed carbene transfer reaction is one of the most notable advances for C-C bond formation reactionsduring the past decade,which has been widely employed in the preparation of C3-substituted indol...Transition metal-catalyzed carbene transfer reaction is one of the most notable advances for C-C bond formation reactionsduring the past decade,which has been widely employed in the preparation of C3-substituted indoles,Here,we described an efficient exa mple of catalyst-and metal-free aminobo ration of alkynes and C—C bond formation with diazo compounds to produce C3-substituted indoles,Diverse alkynyla nilines and diazo compounds ca n be utilized for this tandem transfo rmation under mild reaction conditions,re sulting in broad functional group co mpatibility.Additionally,this metal-free strategy can be extended to construct substituted benzofurans.展开更多
基金grants from the Ministry of Science and Technology of China(2016YFD0101801)the Ministry of Agricultur of China(2016ZX08009003 and 2016ZX08009001)the National Natural Science Foundation of China(31900383 and 31971911).
文摘The bacterium Xanthomonas oryzae pv.Oryzae(Xoo)causes blight in rice worldwide,resulting in signifi-cant crop loss.However,no gene underlying a quantitative trait locus(QTL)for resistance against Xoo has been cloned yet.Here,we report the map-based cloning of a QTL,in which the NBS8R gene confers quantitative resistance to Xoo.NBS8R encodes an NB-ARC protein,which is involved in pathogen/microbe-associated molecular pattern-triggered immunity and whose expression is regulated by non-TAL effector XopQ-inducible Osa-miR1876 through DNA methylation.Sequence analysis of NBS8R in wild rice species and rice cultivars suggests that the Osa-miR1876 binding sites in the 5'UTR of NBS8R are inserted by chance and have undergone variations with Osa-miR1876 throughout evolution.The inter-action between NBS8R and XopQ-inducible Osa-miR1876 is partially in keeping with the zigzag model,revealing that quantitative genes may also follow this model to control the innate immune response or basal disease resistance,and may prove valuable in utilizing the existing landraces that harbor the NBS8R gene but with no Osa-miR1876 binding site in rice breeding for bacterial blight resistance.
基金the National Natural Science Foundation of China(Grants Nos.2167020084 and 21673110)the"Innovation&Entrepreneurship Talents Plan7'of Jiangsu Province for their financial support.
文摘Silylated fluoroalkenes are important synthetic intermediates with complementary reactivity,which play a key role in the construction of natural products,pharmaceuticals,and manmade materials.Converting the normally highly stable fiuoroalkenes into silylated fluoroalkenes by selective defluorosilylation is a challenging task.Herein,we report a simple,inexpensive and robust defluorosilylation of a variety of fluoroalkenes with silylboronates in the presence of alkoxy base to directly synthesize various silylated fluoroalkenes.The protocol features mild and safe reaction conditions that avoid a catalyst,a transition metal,a ligand,and high reaction temperature and tolerates a wide scope of fluoroalkene substrates without compromising the efficiency.Density functional theory calculations show that transient silyl anion complex undergoes an SN2,or SNv substitution,which is responsible for this base-mediated defluorosilylation.
文摘The first Chinese Chemical Letters(CCL)Organic Chemistry Forum was held in Xiamen of Fujian in Jan.2018,followed by the successful events in Zhengzhou of Henan in Dec.2019 and Linzhi of Tibet in July 2021.The series of forums aim to build a high-level organic chemistry academic exchange platform for(Chinese)youthful organic chemists,fully showcase their latest fron-tier achievements,and enhance the international level of organic chemistry in China.At the same time,the convening of the series of forums has also played a positive role in promoting the devel-opment of China’s scientific journal publishing,accelerating the re-alization of the strategic goal of building a world-class journal.
基金We are grateful to Prof. Ping Lu at Fudan University for kindly providing some chiral compounds. We thank the ＂1000-Youth Talents Plan＂, the National Natural Science Foundation of China （Grant 21772002, 21632001 and 2167020084） for financial support. This work was also supported by a program A for Outstanding PhD candidate of Nanjing University.
基金the National Natural Science Foundation of China(Grants 22025104,21972064 and 21901111)the Fundamental Research Funds for the Central Universities for their financial support(Grant 020514380254)The project was also supported by Open Research Fund of School of Chemistry and Chemical Engineering,Henan Normal University.
文摘Monofluoroalkenes are important and versatile privileged components in pharmacologically relevant molecules.Here,we report a method for the selective construction of these compounds in a diversity-oriented fashion through regiodivergent cross-coupling of gem-difluorocyclopropanes with allylboronates by employing a palladium catalyst with two different ligands,in which gem-difluorocyclopropanes were used as allyl electrophiles by C—C and C—F bond activation.In the presence of 2-biphenylyl(diphenyl)phosphine as ligand,the linear-selective allyl–allyl bond formation is highly obtained,while utilizing the sterically hindered BrettPhos(dicyclohexyl[3,6-dimethoxy-2',4',6'-tris(1-methylethyl)[1,1'-biphenyl]-2-yl]phosphine)as the ligand favors the generation of the branched-selective product.Experimental and computational studies investigated the key steps of the cross-coupling reactions,revealing the origin of the ligand-controlled regiodivergence.
基金the National Natural Science Foundation of China (Nos. 22025104, 21972064 and 21901111)the National Natural Science Foundation of Jiangsu Province (No. BK20170632)+2 种基金the Excellent Youth Foundation of Jiangsu Scientific Committee (No. BK20180007)the “Innovation & Entrepreneurship Talents Plan” of Jiangsu Provincethe Fundamental Research Funds for the Central Universities for their financial support
文摘A nickel-catalyzed reductive cross-coupling reactions between polyfluoroarenes and alkyl electrophiles is reported to access substituted fluoroarenes through chelation-assisted C–F activation.Diverse primary and secondary alkyl(pseudo)halides can be employed to couple with polyfluoroarenes,showing excellent regioselectivity.Furthermore,the nickel-catalyzed asymmetric cross-coupling of polyfluoroarenes with racemic alkyl halides is preliminarily explored.In addition,the practicability of the title transformation is also demonstrated by total synthesis of losmapimod and an analog as key steps.The developed method exhibits many advantages,including economic catalytic systems,commercially available alkyl electrophiles,and lack of sensitive organometallic reagents.
基金We thank the National Natural Science Foundation of China(Nos.21672097,21901111)the National Natural Science Foundation of Jiangsu Province(No.BK20170632)for their financial support.
文摘A novel protocol for palladium-catalyzed fluoroarylation of 1,1-difluoroallenes was described here.The reaction proceeded smoothly under mild condition and various trifluoromethylated alkenes were obtained in moderate yields with excellent E selectivity.The mechanism involving a vital trifluoromethylated vinyl silver intermediate,which generated through the F-nucleophilic addition to 1,1-difluoroallenes,has been proposed.
基金supported by the National Natural Science Foundation of China (Nos.21972064 and 21672097)the Excellent Youth Foundation of Jiangsu Scientific Committee (No. BK20180007)the“Innovation & Entrepreneurship Talents Plan” of Jiangsu Province。
文摘Transition metal-catalyzed carbene transfer reaction is one of the most notable advances for C-C bond formation reactionsduring the past decade,which has been widely employed in the preparation of C3-substituted indoles,Here,we described an efficient exa mple of catalyst-and metal-free aminobo ration of alkynes and C—C bond formation with diazo compounds to produce C3-substituted indoles,Diverse alkynyla nilines and diazo compounds ca n be utilized for this tandem transfo rmation under mild reaction conditions,re sulting in broad functional group co mpatibility.Additionally,this metal-free strategy can be extended to construct substituted benzofurans.
