Reductive iodonio-Claisen rearrangement （RICR） involving 23-iodanes and allyl or substituted-allyl silanes in fluoroalcohols, such as 1,1,1,3,3,3-hexafluoroi- sopropanol （HFIP） and 2,2,2-trifluoroethanol （TFE）, ...Reductive iodonio-Claisen rearrangement （RICR） involving 23-iodanes and allyl or substituted-allyl silanes in fluoroalcohols, such as 1,1,1,3,3,3-hexafluoroi- sopropanol （HFIP） and 2,2,2-trifluoroethanol （TFE）, was studied for the synthesis of complex ortho-allyl or substituted-allyl iodoarenes. In comparison to the pre- viously reported condition involving boron trifluoride diethyl etherate, the RICR mediated by fluoroalcohols was found to proceed more effectively. The resulting complex ortho-allyl iodoarenes are useful synthetic intermediates and can be readily converted to various heterocyclic compounds.展开更多
A Ru(II)-catalyzed ortho allylation reaction of N-aryl-7-azaindole with readily available 2-methylidene cyclic carbonate has been developed.This reaction is an effective pathway for synthesizing 7-azaindole derivative...A Ru(II)-catalyzed ortho allylation reaction of N-aryl-7-azaindole with readily available 2-methylidene cyclic carbonate has been developed.This reaction is an effective pathway for synthesizing 7-azaindole derivatives with a wide scope of substrates and high yields.In addition,the method can be extended to the allylation of other heterocyclic compounds and several cyclic carbonates,highlighting the practicality of this strategy for synthesis.展开更多
Tin mediated allylation of aldehydes or ketones in distilled water gives rise to the corresponding homoallyl alcohols in high yield without assistance such as heat, supersonic and acidic media.
Comprehensive Summary Pd-catalyzed asymmetric allylic C—H functionalization has emerged as a powerful tool to access chiral,densely functionalized molecules from easily accessible alkenes,enabling the increase of the...Comprehensive Summary Pd-catalyzed asymmetric allylic C—H functionalization has emerged as a powerful tool to access chiral,densely functionalized molecules from easily accessible alkenes,enabling the increase of the step-or atom-economy by minimizing functional group manipulations for preparing allylating reagents.Due to the inadequacy of stereoselection strategies,the asymmetric allylic C—H functionalization is still in the early stage.In this essay,we will describe our journey to identification of asymmetric catalytic systems,mechanism of allylic C—H activation,control of stereo-and regioselectivity,and applications in asymmetric synthesis.展开更多
We have summarized the developments and advancements of allyl-(aza)allyl coupling reactions in the past years.Since the first report in 1980,Pd-catalyzed allyl-allyl couplings have not drawn chemists'much attentio...We have summarized the developments and advancements of allyl-(aza)allyl coupling reactions in the past years.Since the first report in 1980,Pd-catalyzed allyl-allyl couplings have not drawn chemists'much attention for almost 20 years.Not until the last two decades,transition-metal-catalyzed allyl-(aza)allyl transformations have been retrieved vital interest and significantly developed in many respects,including metal-catalyst,ligand development,mechanistic understanding,substrate scope,and applications in the preparation of complex functional molecules.This review is organized according to the transition metals used in allyl-allyl coupling reactions including our own work.Besides,transition-metal-free,allyl-azaallyl cross-couplings and applications in the total synthesis of natural products and drugs have also been included.展开更多
Novel pentaerythritol-based carbosilane dendrimers centered at carbon have been synthesised. Starting from tetraallyl ether based upon pentaerythritol as the core molecule, a succession of alternate Pt-catalyzed hydro...Novel pentaerythritol-based carbosilane dendrimers centered at carbon have been synthesised. Starting from tetraallyl ether based upon pentaerythritol as the core molecule, a succession of alternate Pt-catalyzed hydrosilyla-tion of allyl groups with HSiCl3 and allylations of SiCl groups thus introduced with CH2=CHCH2MgBr in THF provided a divergent synthesis of three generations of carbosilane dendrimers in which the Si atoms are linked by CH2CH2CH2 groups. The reaction conditions for hydrosilylation must be well controlled. After purification by chromatography on silica gel pure products for each generation were obtained. The IR, 1H and 13C NMR spectra and elemental analysis data are consistent with the proposed structures. The molecular weights of the resulting car-bosilne dendrimers have been determined by vapor pressure osmometry.展开更多
An iridium-catalyzed allylic substitution of sodium phenyl selenide with unsymmetrical allyl carbonates was accomplished, which produced the linear allyl phenyl selenides in 38%--74% yields. An asymmetric irid- ium-ca...An iridium-catalyzed allylic substitution of sodium phenyl selenide with unsymmetrical allyl carbonates was accomplished, which produced the linear allyl phenyl selenides in 38%--74% yields. An asymmetric irid- ium-catalyzed allylation of sodium phenyl selenide was presented as well.展开更多
The asymmetric total synthesis of herbarumin Ⅲ 3, a naturally occurred phytotoxin, along with 8-epi-herbantmin Ⅲ 22, was succeeded in 12 steps from n-butyraldehyde based on Brown＇s asymmetric allylation, taking mod...The asymmetric total synthesis of herbarumin Ⅲ 3, a naturally occurred phytotoxin, along with 8-epi-herbantmin Ⅲ 22, was succeeded in 12 steps from n-butyraldehyde based on Brown＇s asymmetric allylation, taking modified Julia olefination and Yamaguchi＇s macro-lactonization as key steps.展开更多
An efficient,chromium-catalyzed highly enantioselective preparation of protected 1,3-diols has been achieved.In the presence of a chiral chromium catalyst using the carbazole-based bisoxazoline as the chiral ligand,a ...An efficient,chromium-catalyzed highly enantioselective preparation of protected 1,3-diols has been achieved.In the presence of a chiral chromium catalyst using the carbazole-based bisoxazoline as the chiral ligand,a variety of optically pure 1,3-diols were synthesized in 34%-87%yields with up to 98%ee.The benzyl as well as silyl ethers were suitable substitutions for the hydroxyl group.Meanwhile,aromatic,aliphatic and α,β-unsaturated aldehydes are well tolerated under the mild reaction conditions.展开更多
文摘Reductive iodonio-Claisen rearrangement （RICR） involving 23-iodanes and allyl or substituted-allyl silanes in fluoroalcohols, such as 1,1,1,3,3,3-hexafluoroi- sopropanol （HFIP） and 2,2,2-trifluoroethanol （TFE）, was studied for the synthesis of complex ortho-allyl or substituted-allyl iodoarenes. In comparison to the pre- viously reported condition involving boron trifluoride diethyl etherate, the RICR mediated by fluoroalcohols was found to proceed more effectively. The resulting complex ortho-allyl iodoarenes are useful synthetic intermediates and can be readily converted to various heterocyclic compounds.
基金supported by the Natural Science Foundation of Shandong Province(ZR2019BB011)the Scientific Research Foundation of Qingdao University of Science&Technology(010029022).
文摘A Ru(II)-catalyzed ortho allylation reaction of N-aryl-7-azaindole with readily available 2-methylidene cyclic carbonate has been developed.This reaction is an effective pathway for synthesizing 7-azaindole derivatives with a wide scope of substrates and high yields.In addition,the method can be extended to the allylation of other heterocyclic compounds and several cyclic carbonates,highlighting the practicality of this strategy for synthesis.
文摘Tin mediated allylation of aldehydes or ketones in distilled water gives rise to the corresponding homoallyl alcohols in high yield without assistance such as heat, supersonic and acidic media.
基金the National Key R&D Program of China(2021YFA1500100)Youth Innovation Promotion Association CAS(2020448)+3 种基金NSFC(22171254 and 22188101)Anhui Provincial Natural Science Foundation(2108085MB58)USTC Research Funds of the DoubleFirst-Class Initiative(YD2060002024)Start-up Research Fund from University of Science and Technology of China(KY2060000216).
文摘Comprehensive Summary Pd-catalyzed asymmetric allylic C—H functionalization has emerged as a powerful tool to access chiral,densely functionalized molecules from easily accessible alkenes,enabling the increase of the step-or atom-economy by minimizing functional group manipulations for preparing allylating reagents.Due to the inadequacy of stereoselection strategies,the asymmetric allylic C—H functionalization is still in the early stage.In this essay,we will describe our journey to identification of asymmetric catalytic systems,mechanism of allylic C—H activation,control of stereo-and regioselectivity,and applications in asymmetric synthesis.
基金supported by the National Natural Science Foundation of China(No.22201300)the Fundamental Research Funds for the Central Universities,and the Research Funds of Renmin University of China(No.21XNLG04).
文摘We have summarized the developments and advancements of allyl-(aza)allyl coupling reactions in the past years.Since the first report in 1980,Pd-catalyzed allyl-allyl couplings have not drawn chemists'much attention for almost 20 years.Not until the last two decades,transition-metal-catalyzed allyl-(aza)allyl transformations have been retrieved vital interest and significantly developed in many respects,including metal-catalyst,ligand development,mechanistic understanding,substrate scope,and applications in the preparation of complex functional molecules.This review is organized according to the transition metals used in allyl-allyl coupling reactions including our own work.Besides,transition-metal-free,allyl-azaallyl cross-couplings and applications in the total synthesis of natural products and drugs have also been included.
基金Project supported by the National Natural Science Foundation of China (Nos. 29874020,59573029).
文摘Novel pentaerythritol-based carbosilane dendrimers centered at carbon have been synthesised. Starting from tetraallyl ether based upon pentaerythritol as the core molecule, a succession of alternate Pt-catalyzed hydrosilyla-tion of allyl groups with HSiCl3 and allylations of SiCl groups thus introduced with CH2=CHCH2MgBr in THF provided a divergent synthesis of three generations of carbosilane dendrimers in which the Si atoms are linked by CH2CH2CH2 groups. The reaction conditions for hydrosilylation must be well controlled. After purification by chromatography on silica gel pure products for each generation were obtained. The IR, 1H and 13C NMR spectra and elemental analysis data are consistent with the proposed structures. The molecular weights of the resulting car-bosilne dendrimers have been determined by vapor pressure osmometry.
文摘An iridium-catalyzed allylic substitution of sodium phenyl selenide with unsymmetrical allyl carbonates was accomplished, which produced the linear allyl phenyl selenides in 38%--74% yields. An asymmetric irid- ium-catalyzed allylation of sodium phenyl selenide was presented as well.
基金The project was supported by the National Natural Science Foundation of China(No.20672050).
文摘The asymmetric total synthesis of herbarumin Ⅲ 3, a naturally occurred phytotoxin, along with 8-epi-herbantmin Ⅲ 22, was succeeded in 12 steps from n-butyraldehyde based on Brown＇s asymmetric allylation, taking modified Julia olefination and Yamaguchi＇s macro-lactonization as key steps.
基金NSFC(Nos.21421091,XDB20000000)the "Thousand Plan" Youth program for financial support
文摘An efficient,chromium-catalyzed highly enantioselective preparation of protected 1,3-diols has been achieved.In the presence of a chiral chromium catalyst using the carbazole-based bisoxazoline as the chiral ligand,a variety of optically pure 1,3-diols were synthesized in 34%-87%yields with up to 98%ee.The benzyl as well as silyl ethers were suitable substitutions for the hydroxyl group.Meanwhile,aromatic,aliphatic and α,β-unsaturated aldehydes are well tolerated under the mild reaction conditions.
