Ring-closing metathesis reactions involving diallyldiphenylsilane and diallyloxydiphenylsilane were successfully performed by using only 0 01 mol or even less of Grubbs' catalyst 1. The effects of reaction parame...Ring-closing metathesis reactions involving diallyldiphenylsilane and diallyloxydiphenylsilane were successfully performed by using only 0 01 mol or even less of Grubbs' catalyst 1. The effects of reaction parameters, such as solvents, temperature and concentration of the catalyst are discussed.展开更多
A pentamodule assembly approach has been established for total synthesis of the naturally occurring(-)-palmyrolide A and(+)-5,7-epi-palmyrolide A.By using the racemic tert-butyl carbinol-containing alkyl iodide,the tw...A pentamodule assembly approach has been established for total synthesis of the naturally occurring(-)-palmyrolide A and(+)-5,7-epi-palmyrolide A.By using the racemic tert-butyl carbinol-containing alkyl iodide,the two diastereoisomeric macrolides could be obtained from the same sequence of reactions,demonstrating the flexibility of the multimodule assembly strategy for diverted total synthesis.展开更多
The carbonyl-olefin ring-closing metathesis reactions have become a powerful tool for carbon-carbon bond formation.In this work,the halogen bond catalysis and classical Lewis acid catalysis on the carbonyl-olefin ring...The carbonyl-olefin ring-closing metathesis reactions have become a powerful tool for carbon-carbon bond formation.In this work,the halogen bond catalysis and classical Lewis acid catalysis on the carbonyl-olefin ring-closing metathesis reaction were investigated by density function theory.For both the halogen bond catalysis and classical Lewis acid catalysis,the carbonyl-olefin ring-closing me-tathesis reaction occurs by[2+2]-cycloaddition process and[2+2]-cycloreversion process,the reaction energy barriers are low,there-fore,it can be performed easily at room temperature.The essential difference of the two kinds of catalysts is that the catalytic mecha-nism of halogen bond catalysis is mainly contribution of electrostatic interaction,while that of classical Lewis acid catalysis is mainly catalyzed by orbital interaction.The halogen bond donor catalysts(ICI_(3),IF_(3))are expected to be efficient catalysts for the reaction and further promote the chemical synthesis of carbonyl-olefin ring-closing metathesis reaction.展开更多
A series of succinate-derived macrocyclic amides（1） was synthesized via ring-closing metathesis（RCM） as the key step. The substrate included 12 to 15 members. The metathesis precursors were obtained from the amide...A series of succinate-derived macrocyclic amides（1） was synthesized via ring-closing metathesis（RCM） as the key step. The substrate included 12 to 15 members. The metathesis precursors were obtained from the amide coupling of ten-butyl 3-carboxyhex-5-enoate（2） with numerous side-chain aikenylated amino acid esters of general type（3） derived from L-lysine and L-ornithine.展开更多
The development of degradable polymers represents an appealing strategy to address ever-growing concerns for treating waste plastics.Olefin metathesis polymerization has been extensively explored for the synthesis of ...The development of degradable polymers represents an appealing strategy to address ever-growing concerns for treating waste plastics.Olefin metathesis polymerization has been extensively explored for the synthesis of various degradable polymers.Cyclic–acyclic monomers metathesis polymerization(CAMMP)has recently been reported to produce degradable polymers via copolymerization of cyclic monomers with acyclic diene comonomers.Unfortunately,this strategy suffers from poor product material properties,especially at high contents of diene comonomers.To address this issue,we have designed a tandem olefin metathesis polymerization(TOMP)system that combines olefin ringclosing metathesis(RCM)of diene comonomers,followed by ring-opening metathesis copolymerization(ROMCP)with cyclic olefin monomers(dicyclopentadiene,cyclooctene,or alkyl-substituted cyclooctene).This strategy overcame the intrinsic limitations of diene-induced chain-transfer reactions during olefin metathesis,leading to degradable polymers with high molecular weights and excellent material properties.The selection of different cyclic olefin monomers provided access to degradable and recyclable cross-linked thermosets,linear thermoplastics,and elastomers.Notably,this one-pot,two-step process was highly efficient and required the addition of only one metathesis catalyst.展开更多
Polymer chain architectures play a crucial role in the physical properties of polymers and this unique phenomenon has been recognized as the topological effects.As one of the most representative architectures,macrocyc...Polymer chain architectures play a crucial role in the physical properties of polymers and this unique phenomenon has been recognized as the topological effects.As one of the most representative architectures,macrocyclic polymers characterized by the endless topology have received extensive attention due to their distinct physical properties as compared to the linear counterparts.To understand these differences and unravel the underlying mechanisms,there is a long pursuit to efficiently fabricate macrocyclic polymers.To date,both ring-closing and ring-expansion strategies have been developed,which drastically elevates the accessibility of macrocyclic polymers.The improved availability of macrocyclic polymers enables the further investigation of the biomedical applications and the preliminary results suggest that macrocyclic polymers outperform their linear analogs in terms of improving gene delivery efficiency,elevating blood circulation time,and enhancing colloidal stability of nanoparticles.展开更多
The efficient synthesis of （S）-dihydroresorcylide （la） along with trans-resorcylide dimethyl ether （2b）, was achieved in linear 9 steps from commercially available orcinol monohydrate （6） with esterification, ...The efficient synthesis of （S）-dihydroresorcylide （la） along with trans-resorcylide dimethyl ether （2b）, was achieved in linear 9 steps from commercially available orcinol monohydrate （6） with esterification, carbonylation, and ring-closing metathesis （RCM） as the key steps in the synthetic sequence.展开更多
文摘Ring-closing metathesis reactions involving diallyldiphenylsilane and diallyloxydiphenylsilane were successfully performed by using only 0 01 mol or even less of Grubbs' catalyst 1. The effects of reaction parameters, such as solvents, temperature and concentration of the catalyst are discussed.
基金This work is supported in part by a General Research Fund grant(601211)from the Research Grant CouncilThe Hong Kong Special Administrative Region,P.R.China+1 种基金The Hong Kong Chiu Chow Chamber of Commence HKUST Scholarship for Ph.D.Study(Y.L.)the Department of Chemistry,HKUST.
文摘A pentamodule assembly approach has been established for total synthesis of the naturally occurring(-)-palmyrolide A and(+)-5,7-epi-palmyrolide A.By using the racemic tert-butyl carbinol-containing alkyl iodide,the two diastereoisomeric macrolides could be obtained from the same sequence of reactions,demonstrating the flexibility of the multimodule assembly strategy for diverted total synthesis.
基金This work was supported by the Natural Science Foundation of Hebei Province(B2019205113,B2019205061)the National Natural Science Foundation of China(21973025)the Science Foundation of Hebei Normal University(L2020Z04).
文摘The carbonyl-olefin ring-closing metathesis reactions have become a powerful tool for carbon-carbon bond formation.In this work,the halogen bond catalysis and classical Lewis acid catalysis on the carbonyl-olefin ring-closing metathesis reaction were investigated by density function theory.For both the halogen bond catalysis and classical Lewis acid catalysis,the carbonyl-olefin ring-closing me-tathesis reaction occurs by[2+2]-cycloaddition process and[2+2]-cycloreversion process,the reaction energy barriers are low,there-fore,it can be performed easily at room temperature.The essential difference of the two kinds of catalysts is that the catalytic mecha-nism of halogen bond catalysis is mainly contribution of electrostatic interaction,while that of classical Lewis acid catalysis is mainly catalyzed by orbital interaction.The halogen bond donor catalysts(ICI_(3),IF_(3))are expected to be efficient catalysts for the reaction and further promote the chemical synthesis of carbonyl-olefin ring-closing metathesis reaction.
基金Supported partly by Key Program of Ministry of Education of China(No. 104112)
文摘A series of succinate-derived macrocyclic amides（1） was synthesized via ring-closing metathesis（RCM） as the key step. The substrate included 12 to 15 members. The metathesis precursors were obtained from the amide coupling of ten-butyl 3-carboxyhex-5-enoate（2） with numerous side-chain aikenylated amino acid esters of general type（3） derived from L-lysine and L-ornithine.
基金supported by National Key R&D Program of China(grant no.2021YFA1501700)National Natural Science Foundation of China(NSFC+3 种基金grant nos.22301294,52025031,and 22261142664)the Chinese Academy of Sciences(CAS)Project for Young Scientists in Basic Research(grant no.YSBR-094)China Postdoctoral Science Foundation(grant nos.BX20230339 and 2023M743352)the University of Science and Technology of China(USTC)Research Funds of the Double First-Class Initiative(grant no.YD9990002030).
文摘The development of degradable polymers represents an appealing strategy to address ever-growing concerns for treating waste plastics.Olefin metathesis polymerization has been extensively explored for the synthesis of various degradable polymers.Cyclic–acyclic monomers metathesis polymerization(CAMMP)has recently been reported to produce degradable polymers via copolymerization of cyclic monomers with acyclic diene comonomers.Unfortunately,this strategy suffers from poor product material properties,especially at high contents of diene comonomers.To address this issue,we have designed a tandem olefin metathesis polymerization(TOMP)system that combines olefin ringclosing metathesis(RCM)of diene comonomers,followed by ring-opening metathesis copolymerization(ROMCP)with cyclic olefin monomers(dicyclopentadiene,cyclooctene,or alkyl-substituted cyclooctene).This strategy overcame the intrinsic limitations of diene-induced chain-transfer reactions during olefin metathesis,leading to degradable polymers with high molecular weights and excellent material properties.The selection of different cyclic olefin monomers provided access to degradable and recyclable cross-linked thermosets,linear thermoplastics,and elastomers.Notably,this one-pot,two-step process was highly efficient and required the addition of only one metathesis catalyst.
基金supported by the National Natural Science Foundation of China(51690150,51690154,21674103,51673179)International S&T Cooperation Program of China of MOST(2016YFE0129700)
文摘Polymer chain architectures play a crucial role in the physical properties of polymers and this unique phenomenon has been recognized as the topological effects.As one of the most representative architectures,macrocyclic polymers characterized by the endless topology have received extensive attention due to their distinct physical properties as compared to the linear counterparts.To understand these differences and unravel the underlying mechanisms,there is a long pursuit to efficiently fabricate macrocyclic polymers.To date,both ring-closing and ring-expansion strategies have been developed,which drastically elevates the accessibility of macrocyclic polymers.The improved availability of macrocyclic polymers enables the further investigation of the biomedical applications and the preliminary results suggest that macrocyclic polymers outperform their linear analogs in terms of improving gene delivery efficiency,elevating blood circulation time,and enhancing colloidal stability of nanoparticles.
基金This research work was financially supported by the Natural Science Foundation of China （Nos. 21021063, 81273430）, the National Marine ＂863＂ Project （Nos. 2011AA09070102 and 2013AA092902） and the SKLDR/SIMM Projects （No. SIMM1203ZZ-03）. We also thank Professor Minghua Xu （SIMM-CAS） for helpful discussion in preparation of this manuscript.
文摘The efficient synthesis of （S）-dihydroresorcylide （la） along with trans-resorcylide dimethyl ether （2b）, was achieved in linear 9 steps from commercially available orcinol monohydrate （6） with esterification, carbonylation, and ring-closing metathesis （RCM） as the key steps in the synthetic sequence.
