of main observation and conclusion Oxygen atom transfer reactions between alkynes and heteroarene N-oxides are currently mediated by transition metal,such as gold,ruthenium or rhodium,but they have never been catalyze...of main observation and conclusion Oxygen atom transfer reactions between alkynes and heteroarene N-oxides are currently mediated by transition metal,such as gold,ruthenium or rhodium,but they have never been catalyzed by osmium.Herein,we report stepwise oxidations of terminal alkynes mediated by an osmium carbolong complex,using pyridine N-oxide as the oxidant,yielding novel aldehyde-or carboxylic acid-coordinated osmapentalyne derivatives selectively.The mechanism was illustrated by density functional theory calculations,providing a new route for oxygen atom transfer between heteroarene N-oxides and alkynes.展开更多
Three-membered unsaturated rings have been widely utilized in organic synthesis due to their inherent highly strained structures.Although much research has been applied to ring-expansion reactions of such strained rin...Three-membered unsaturated rings have been widely utilized in organic synthesis due to their inherent highly strained structures.Although much research has been applied to ring-expansion reactions of such strained ring systems,pathways other than[3+2]cycloadditions have rarely been observed in their reactions with alkynes,and to date,no[3+1]cycloadditions of isolated three-membered unsaturated rings with alkynes have been reported.Here we demonstrate an unprecedented[3+1]cycloaddition in which a fused metalla-azirine is used as a template to generate a series of planar CCCCX-type(X=N,O,S)pentadentate carbolong complexes 3–6.A series of substituted alkynes was tested for further exploration of the scope and mechanism for the[3+1]cycloaddition reactions.Complexes 3–6 represent rare examples of planar pentadentate complexes that assemble fourπ-conjugated fused rings by one bridgehead atom.These novel complexes are thermally stable in air and absorb ultraviolet,visible,and near-infrared light,and thus are potentially applicable in photoelectric devices and pharmaceuticals.展开更多
Over the last decades,the treatment of the large quantities of hypersaline wastewater generated by conventional industries,inland desalination,and fossil-fueled power plants has been an important economic issue and al...Over the last decades,the treatment of the large quantities of hypersaline wastewater generated by conventional industries,inland desalination,and fossil-fueled power plants has been an important economic issue and also an inescapable green issue.Here,we developed a versatile interfacial heating membrane with alternating utilization of electricity or solar energy for hypersaline water treat-ment.This hierarchical membrane functions both as a separation membrane and an interface heater,which can quickly(<0.1 s)convert electricity or solar energy into heat to evaporate the outermost layer of hypersaline water.For 10wt% hyper-saline water,the freshwater production rate can reach 16.8kg/m^(2)⋅h by applying a voltage of 10 V and 1.36 kg/m^(2)⋅h under 1-sun illumination.Moreover,it exhibits high electrochemical resistance to corrosion and therefore remains stable tack-ling hypersaline water(>5 wt%),with a high salt rejection rate of 99.99%.This system shows an efficient desalination strategy that can provide fresh water from brines for agriculture and industry,and even for daily life.展开更多
Atkamine is a complex marine pyrroloiminoquinone alkaloid that comprises a heptacyclic scaffold bearing five different heterocycles and four contiguous stereocenters,and therefore it is a highly challenging target for...Atkamine is a complex marine pyrroloiminoquinone alkaloid that comprises a heptacyclic scaffold bearing five different heterocycles and four contiguous stereocenters,and therefore it is a highly challenging target for synthetic chemists.We herein reported a modular synthetic strategy toward this alkaloid,featuring a formal [5+2] annulation and an asymmetric Michael addition.The efficient synthesis of the long-chain aliphatic aldehyde and chiral amino acetal fragments have been achieved.A simplified tetracyclic intermediate bearing the core structure of atkamine has been successfully constructed through the formal [5+2] annulation.展开更多
A unified protecting group-free approach to two stemarene and two betaerene diterpenoids through a bioinspired two-phase strategy has been developed,and three of them were obtained for the first time via chemical synt...A unified protecting group-free approach to two stemarene and two betaerene diterpenoids through a bioinspired two-phase strategy has been developed,and three of them were obtained for the first time via chemical synthesis.Starting from a common intermediate,two distinct tetracyclic frameworks containing diastereoisomeric bridged bicycles were constructed by a divergent ring reorganization strategy.Late-stage C–H functionalization through a xanthylation-oxygenation protocol furnished the corresponding oxygenated stereocenters or oxo functionality in high regio-and diastereoselective fashion within a complex hydrocarbon system.The stereochemical puzzles in(–)-2-acetoxybetaer13(17)-ene and(+)-7-acetoxybetaer-13(17)-ene were first predicted by the comparison of density functional theory(DFT)-nuclear magnetic resonance(NMR)data with the reported data and then unambiguously addressed through the total syntheses of natural products and three diastereomers.展开更多
基金We gratefully acknowledge the Guangdong Provincial Key Laboratory of Catalysis(No.2020B121201002)NSFC(Nos.U1705254 and 21931002)for their financial support.
文摘of main observation and conclusion Oxygen atom transfer reactions between alkynes and heteroarene N-oxides are currently mediated by transition metal,such as gold,ruthenium or rhodium,but they have never been catalyzed by osmium.Herein,we report stepwise oxidations of terminal alkynes mediated by an osmium carbolong complex,using pyridine N-oxide as the oxidant,yielding novel aldehyde-or carboxylic acid-coordinated osmapentalyne derivatives selectively.The mechanism was illustrated by density functional theory calculations,providing a new route for oxygen atom transfer between heteroarene N-oxides and alkynes.
基金supported by the National Natural Science Foundation of China(U1705254,21871225,and 21931002)the Fundamental Research Funds for the Central Universities(20720190042),and the Research Grants Council of Hong Kong(N_HKUST603/15).
文摘Three-membered unsaturated rings have been widely utilized in organic synthesis due to their inherent highly strained structures.Although much research has been applied to ring-expansion reactions of such strained ring systems,pathways other than[3+2]cycloadditions have rarely been observed in their reactions with alkynes,and to date,no[3+1]cycloadditions of isolated three-membered unsaturated rings with alkynes have been reported.Here we demonstrate an unprecedented[3+1]cycloaddition in which a fused metalla-azirine is used as a template to generate a series of planar CCCCX-type(X=N,O,S)pentadentate carbolong complexes 3–6.A series of substituted alkynes was tested for further exploration of the scope and mechanism for the[3+1]cycloaddition reactions.Complexes 3–6 represent rare examples of planar pentadentate complexes that assemble fourπ-conjugated fused rings by one bridgehead atom.These novel complexes are thermally stable in air and absorb ultraviolet,visible,and near-infrared light,and thus are potentially applicable in photoelectric devices and pharmaceuticals.
基金National Key R&D Program of China,Grant/Award Number:2018YFA0209500National Natural Science Foundation of China,Grant/Award Numbers:21621091,21975209,52025132。
文摘Over the last decades,the treatment of the large quantities of hypersaline wastewater generated by conventional industries,inland desalination,and fossil-fueled power plants has been an important economic issue and also an inescapable green issue.Here,we developed a versatile interfacial heating membrane with alternating utilization of electricity or solar energy for hypersaline water treat-ment.This hierarchical membrane functions both as a separation membrane and an interface heater,which can quickly(<0.1 s)convert electricity or solar energy into heat to evaporate the outermost layer of hypersaline water.For 10wt% hyper-saline water,the freshwater production rate can reach 16.8kg/m^(2)⋅h by applying a voltage of 10 V and 1.36 kg/m^(2)⋅h under 1-sun illumination.Moreover,it exhibits high electrochemical resistance to corrosion and therefore remains stable tack-ling hypersaline water(>5 wt%),with a high salt rejection rate of 99.99%.This system shows an efficient desalination strategy that can provide fresh water from brines for agriculture and industry,and even for daily life.
基金the National Natural Science Foundation of China for financial support of this work by grants (Nos.21772164 and 21572187)the National Found for Fostering Talents of Basic Science (NFFTBS,No.J1310024)+1 种基金New Century Excellent Talents in University of Fujian Province (NECTFJ)Program for Changjiang Scholars and Innovative Research Team in University (PCSIRT) for support。
文摘Atkamine is a complex marine pyrroloiminoquinone alkaloid that comprises a heptacyclic scaffold bearing five different heterocycles and four contiguous stereocenters,and therefore it is a highly challenging target for synthetic chemists.We herein reported a modular synthetic strategy toward this alkaloid,featuring a formal [5+2] annulation and an asymmetric Michael addition.The efficient synthesis of the long-chain aliphatic aldehyde and chiral amino acetal fragments have been achieved.A simplified tetracyclic intermediate bearing the core structure of atkamine has been successfully constructed through the formal [5+2] annulation.
基金Financial support from the National Natural Science Foundation of China(nos.22071205,21772164,and 21572187)NFFTBS(no.J1310024),and PCSIRT is acknowledged.
文摘A unified protecting group-free approach to two stemarene and two betaerene diterpenoids through a bioinspired two-phase strategy has been developed,and three of them were obtained for the first time via chemical synthesis.Starting from a common intermediate,two distinct tetracyclic frameworks containing diastereoisomeric bridged bicycles were constructed by a divergent ring reorganization strategy.Late-stage C–H functionalization through a xanthylation-oxygenation protocol furnished the corresponding oxygenated stereocenters or oxo functionality in high regio-and diastereoselective fashion within a complex hydrocarbon system.The stereochemical puzzles in(–)-2-acetoxybetaer13(17)-ene and(+)-7-acetoxybetaer-13(17)-ene were first predicted by the comparison of density functional theory(DFT)-nuclear magnetic resonance(NMR)data with the reported data and then unambiguously addressed through the total syntheses of natural products and three diastereomers.
