A general method was described to synthesize a highly hydrophobic cyclic peptide,cyclo[LWLWLWLWLQ]where underlines indicate D-configuration of the amino acid,by a two-step solid-phase/solution synthesis strategy.The l...A general method was described to synthesize a highly hydrophobic cyclic peptide,cyclo[LWLWLWLWLQ]where underlines indicate D-configuration of the amino acid,by a two-step solid-phase/solution synthesis strategy.The linear decapeptide was assembled by standard Boc chemistry on solid-phase and subsequently cyclized in solution with high efficiency and reproducibility. In subsequent purification by semi-preparative HPLC,50%(v/v) DMF/H_2O was employed as the solvent to overcome the difficulty of solubilization...展开更多
Cyclopeptidomimetics are class of cyclopeptides with unnatural linkage. They usually displayed unique constrained structure, enhanced proteolytic stability, and other drug-like character; and have been widely used in ...Cyclopeptidomimetics are class of cyclopeptides with unnatural linkage. They usually displayed unique constrained structure, enhanced proteolytic stability, and other drug-like character; and have been widely used in medicinal chemistry. Therefore, development of efficient strategies for the synthesis of cyclopeptidomimetics has received many attentions. On-resin cyclization strategy is one of the effective approaches developed to overcome the competing side reaction such as oligomerization and cyclooligomers occurred in solution cyclization. This approach took advantage of the ＂pseudo-dilution＂ effect to avoid these undesired by-products and greatly simplified the downstream product purification process. This review summarized the recent on-resin peptide cyclization strategies for the synthesis of cvclooeotidomimetics.展开更多
A green protocol for the synthesis of quinoxalines has been developed from catalytic oxidative cyclization of deoxybenzoins with 1,2-phenylenediamines in water.The optimal conditions are involved in the use of a water...A green protocol for the synthesis of quinoxalines has been developed from catalytic oxidative cyclization of deoxybenzoins with 1,2-phenylenediamines in water.The optimal conditions are involved in the use of a water-soluble mononuclear copper（Ⅱ） complex of a zwitterionic calix[4]arene[Cu（Ⅱ）LCH2O）]I2（1,H4L=[5,ll,17,23-tetrakis（trimethylammonium）-25,26,27,28-tetrahydroxycalix[4]arene]） as a catalyst in alkali solution after refluxing for 15 h in O2.The target quinoxaline and its derivatives were obtained in good yields（up to 88%）.The procedure described in this paper is simple,practical and environmentally benign.展开更多
A convenient cyclization method for the flavans synthesis is described. BF3 was used for the first time as an efficient catalyst to effect the cyclization of 1,3-diarylpropan-1-ols.
The Lewis acid mediated polystyrene supported selenium cyclization of chalcones and oxidative cleavage of selenium resins flavonoids in good yields and purities have been reported. induced intramolecular gave the cor...The Lewis acid mediated polystyrene supported selenium cyclization of chalcones and oxidative cleavage of selenium resins flavonoids in good yields and purities have been reported. induced intramolecular gave the corresponding展开更多
In this study, we applied a novel, mild, and convenient synthetic method involving the oxidative cyclization of 1-(pyrazin-2-yl)guanidine derivatives to produce [1,2,4]triazolo[4,3-a ]pyrazin-3-amines. We optimized th...In this study, we applied a novel, mild, and convenient synthetic method involving the oxidative cyclization of 1-(pyrazin-2-yl)guanidine derivatives to produce [1,2,4]triazolo[4,3-a ]pyrazin-3-amines. We optimized the reaction procedure to easily obtain 5-chloro-[1,2,4]triazolo[4,3-a ]pyrazin-3-amine. Various types of halogenated pyrazines can successfully undergo this process. We synthesized a series of 1-(pyrazin-2-yl)guanidines and [1,2,4]triazolo[4,3-a ]pyrazin-3-amines, and then elucidated their structures based on their ~1H-NMR, ^(13)C-NMR, ESI-HRMS, and nuclear Overhauser effect spectra.展开更多
An effective approach for the construction of the decalin ring skeleton of labdane diterpenoids was developed based on a key biomimetic cationic polyene cyclization of an epoxy allylsilane precursor. The synthetic a...An effective approach for the construction of the decalin ring skeleton of labdane diterpenoids was developed based on a key biomimetic cationic polyene cyclization of an epoxy allylsilane precursor. The synthetic approach demonstrated here would be useful in the enantioselective and diastereoselective total synthesis of natural labdane diterpenoids in general.展开更多
An atmospheric-oxygen-mediated four-component reaction was developed for the divergent synthesis of pyrazolo[1,5-a]pyrimidine and pyrazolo[3,4-b]pyridine derivatives from readily available alcohols and 3-aminopyrazole...An atmospheric-oxygen-mediated four-component reaction was developed for the divergent synthesis of pyrazolo[1,5-a]pyrimidine and pyrazolo[3,4-b]pyridine derivatives from readily available alcohols and 3-aminopyrazoles.In this transformation,atmospheric oxygen serves as the green oxidant,promoting alcohols as equivalent aldehydes for the synthesis of four types of N-containing heterocycles(>40 examples).Remarkably,the transformation features metal-free and molecular diversity.展开更多
Muscone is a precious fragrant compound scarce in nature. Many attempts have been made to synthesize this unique natural product. In this work, the one-carbon unit transfer reaction of tetrahydrofolate coenzyme was in...Muscone is a precious fragrant compound scarce in nature. Many attempts have been made to synthesize this unique natural product. In this work, the one-carbon unit transfer reaction of tetrahydrofolate coenzyme was initiated. Benzimidazolium salt was used as the tetrahydrofolate coenzyme model at formic acid oxidation level and di-Grignard reagent as the nucleophile to which one-carbon unit was transferred; the biomimetic synthesis of 2,15-hexade-canedione, a precursor of muscone, was successfully accomplished by using the addition-hydrolysis reaction of benzimidazolium salt with Grignard reagent. And an important useful method for the synthesis of muscone is provided.展开更多
Halocyclization of olefinic substrate enables the establishment of cyclic skeletons via intramolecular halonium-induced nucleophilic addition,which has been well utilized as a practical strategy for constructing cycli...Halocyclization of olefinic substrate enables the establishment of cyclic skeletons via intramolecular halonium-induced nucleophilic addition,which has been well utilized as a practical strategy for constructing cyclic skeletons in natural product synthesis.Recently,the renaissance and rapid evolution of organocatalysis have accelerated the development of catalytic asymmetric halocyclization.In this context,natural product synthesis powered by catalytic asymmetric halocyclization has also achieved considerable progress in recent years.In some cases,these newly developed protocols enable more concise synthetic routes for accessing enantioenriched natural products.To this end,this review summarizes the applications of catalytic asymmetric halocyclization in natural product synthesis.展开更多
Lycopodium alkaloids, a unique family of biologically important natural products isolated and characterized from various species of Lycopodium(sensu lato), have attracted extensive attention from chemists and pharmaci...Lycopodium alkaloids, a unique family of biologically important natural products isolated and characterized from various species of Lycopodium(sensu lato), have attracted extensive attention from chemists and pharmacists in the past three decades. Michael addition-based cyclization has been successfully employed as an elegant and efficient ring-construction protocol of constructing key cyclohexanone intermediates in the total synthesis of Lycopodium alkaloids. This mini-review chooses and summarizes several representative total syntheses of various Lycopodium alkaloids in which intramolecular Michael addition severed as the key methodology.展开更多
To achieve head-to-tail cyclic peptides via the liquid-phase on-support cyclization and synergistic self-cleavage strategy,4,4’-bis(diphenylphosphinyloxyl)diphenyl ketoxime(BDKO)and 4-diphenyl phospho-loxy benzyl alc...To achieve head-to-tail cyclic peptides via the liquid-phase on-support cyclization and synergistic self-cleavage strategy,4,4’-bis(diphenylphosphinyloxyl)diphenyl ketoxime(BDKO)and 4-diphenyl phospho-loxy benzyl alcohol(DPBA)were designed and prepared as small-molecular supports of greener peptide synthesis.In the process of the BDKO(or DPBA)support assisted Boc strategy for liquid-phase peptide chain extension,the last amino acid at the N-terminus of the peptide chain ends with a Fmoc protected amino acid.展开更多
In the presence of Cu（OAc）2·H2O, a variety of 5-trifluoromethyl-2,4-disubstituted oxazoles were easily synthesized via t-BuOOH （TBHP）/I2-mediated tandem oxidative cyclization from readily available starting m...In the presence of Cu（OAc）2·H2O, a variety of 5-trifluoromethyl-2,4-disubstituted oxazoles were easily synthesized via t-BuOOH （TBHP）/I2-mediated tandem oxidative cyclization from readily available starting materials aryl methanamines and α-trifluoroacetyl-substituted ketones or esters under mild conditions, The mechanism was proposed.展开更多
Comprehensive Summary An asymmetric synthesis of dihydrospirotryprostatin B was achieved in 15 steps(8 purifications)from L-tryptophan.The main feature of our synthetic strategy is the efficient construction of spiroc...Comprehensive Summary An asymmetric synthesis of dihydrospirotryprostatin B was achieved in 15 steps(8 purifications)from L-tryptophan.The main feature of our synthetic strategy is the efficient construction of spirocyclic oxindole intermediate containing a chiral quaternary carbon center,involving the silica gel-mediated cyclization of tryptamine-ynamide and oxidation under neat conditions.展开更多
Lignans have been established as a privileged scaffold in drug discovery,particularly in anticancer and antioxidant properties.Concise and efficient construction of lignans and their derivatives in a single operation ...Lignans have been established as a privileged scaffold in drug discovery,particularly in anticancer and antioxidant properties.Concise and efficient construction of lignans and their derivatives in a single operation holds great medicinal significance for structure-activity relationship studies yet remains challenging.Drawing inspiration from the biosynthesis of lignans,we present a general,high-step-economy palladium-catalyzed reaction that converts simple chemical feedstocks into dehydrodibenzylbutyrolactone lignans through the in-situ construction and coupling of two phenylpropanoid molecules.The diversity of organoboronic acids and the editability of enyne provide a powerful platform for the rapid construction of lignan libraries,featuring 82 lignans analogs,collective syntheses of 10 distinct lignan skeletons,and 13 hybrid molecules combining pharmacophore fragments with drug and derivatives.The subtle combination of phosphine ligands with quinones for switching chemoselectivity is vital to the success of this protocol.展开更多
Comprehensive Summary.Nitrogen-containing bridged-heterocycles and indoles are key subunits of many natural products and pharmacologically active molecules.We herein present a bimetallic Cu/Ir catalyzed asymmetric all...Comprehensive Summary.Nitrogen-containing bridged-heterocycles and indoles are key subunits of many natural products and pharmacologically active molecules.We herein present a bimetallic Cu/Ir catalyzed asymmetric allylation of ketimine esters and(E)-4-indolyl allyl carbonates followed by acid-promoted Pictet-Spengler cyclization sequences,enabling stereodivergent synthesis of chiral indole fused 9-azabicyclo[4.2.1]nonanes containing an eight-membered ring with one tertiary and two quaternary stereogenic centers.This one-pot sequential protocol features step economy,good substrate tolerance,and excellent stereoselective control.展开更多
A series of novel cyclic derivatives have been synthesized by utilizing a nickel powder mediated radical cyclization as the key step. The structures of the new compounds were confirmed by 1H-NMR and MS.
The first synthesis of the naturally occurring cyclic peptide euryjanicin B has been achieved.A general method was described to synthesize the cyclic peptide by a two-step solid-phase/solution synthesis strategy.All t...The first synthesis of the naturally occurring cyclic peptide euryjanicin B has been achieved.A general method was described to synthesize the cyclic peptide by a two-step solid-phase/solution synthesis strategy.All the amino acids in this study are L-configuration. The linear heptapeptide was assembled by standard Fmoc chemistry on solid-phase and subsequently cyclization was carried out by solution method.展开更多
Terpenoids comprise the largest family of natural products and include various structurally different genus which play important roles in living organisms. Biosynthetically, diterpenoids are derived from （E,E,E）-ger...Terpenoids comprise the largest family of natural products and include various structurally different genus which play important roles in living organisms. Biosynthetically, diterpenoids are derived from （E,E,E）-geranylgeranyl diphosphate （GGPP）. From GGPP, diterpene cyclase catalyzes a sequence of carbocation- mediated cyclizations, rearrangements, and further oxidations, leading to a class of structurally unique ent-kaurenes, such as cafestol, gibberellin A3 and oridonin. According to the biosynthesis pathway of ent-kaurene, we designed a chiral acetal-enabled and SnCln-promoted biomimetic polyene cationic cyclization. With a following Birch reduc- tiort/alkylation cascade, a core skeleton of representative ent-kaurenes diterpenoids was completed.展开更多
基金supported by National Natural Science Foundation(No.30672546)Shanghai Municipal Committee of S & T(No.0652nm013)National Key Basic Research Program of China(No.2007CB935800)
文摘A general method was described to synthesize a highly hydrophobic cyclic peptide,cyclo[LWLWLWLWLQ]where underlines indicate D-configuration of the amino acid,by a two-step solid-phase/solution synthesis strategy.The linear decapeptide was assembled by standard Boc chemistry on solid-phase and subsequently cyclized in solution with high efficiency and reproducibility. In subsequent purification by semi-preparative HPLC,50%(v/v) DMF/H_2O was employed as the solvent to overcome the difficulty of solubilization...
基金supported by the National Natural Science Foundation of China (No.21472070)the Project for Jiangsu Scientific and Technological Innovation Team+1 种基金Fund for Jiangsu Distinguished Professorship ProgramProject Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions,the 111 Project (No.111-2-06)
文摘Cyclopeptidomimetics are class of cyclopeptides with unnatural linkage. They usually displayed unique constrained structure, enhanced proteolytic stability, and other drug-like character; and have been widely used in medicinal chemistry. Therefore, development of efficient strategies for the synthesis of cyclopeptidomimetics has received many attentions. On-resin cyclization strategy is one of the effective approaches developed to overcome the competing side reaction such as oligomerization and cyclooligomers occurred in solution cyclization. This approach took advantage of the ＂pseudo-dilution＂ effect to avoid these undesired by-products and greatly simplified the downstream product purification process. This review summarized the recent on-resin peptide cyclization strategies for the synthesis of cvclooeotidomimetics.
基金the financial supports from the National Natural Science Foundation of China(Nos.21271134, 21373142,21531006 and 21671144)the State Key Laboratory of Organometallic Chemistry,Shanghai Institute of Organic Chemistry(No.2015kf-07)+2 种基金supports from the "333" Project of Jiangsu Provincethe Priority Academic Program Development of Jiangsu Higher Education Institutionsthe "SooChow Scholar" Program of Soochow University
文摘A green protocol for the synthesis of quinoxalines has been developed from catalytic oxidative cyclization of deoxybenzoins with 1,2-phenylenediamines in water.The optimal conditions are involved in the use of a water-soluble mononuclear copper（Ⅱ） complex of a zwitterionic calix[4]arene[Cu（Ⅱ）LCH2O）]I2（1,H4L=[5,ll,17,23-tetrakis（trimethylammonium）-25,26,27,28-tetrahydroxycalix[4]arene]） as a catalyst in alkali solution after refluxing for 15 h in O2.The target quinoxaline and its derivatives were obtained in good yields（up to 88%）.The procedure described in this paper is simple,practical and environmentally benign.
文摘A convenient cyclization method for the flavans synthesis is described. BF3 was used for the first time as an efficient catalyst to effect the cyclization of 1,3-diarylpropan-1-ols.
基金the National Natural Science Foundation of China （No. 20332050）
文摘The Lewis acid mediated polystyrene supported selenium cyclization of chalcones and oxidative cleavage of selenium resins flavonoids in good yields and purities have been reported. induced intramolecular gave the corresponding
基金supported by the National Nature Science Foundation of China(Nos.21576195 and 21776207)
文摘In this study, we applied a novel, mild, and convenient synthetic method involving the oxidative cyclization of 1-(pyrazin-2-yl)guanidine derivatives to produce [1,2,4]triazolo[4,3-a ]pyrazin-3-amines. We optimized the reaction procedure to easily obtain 5-chloro-[1,2,4]triazolo[4,3-a ]pyrazin-3-amine. Various types of halogenated pyrazines can successfully undergo this process. We synthesized a series of 1-(pyrazin-2-yl)guanidines and [1,2,4]triazolo[4,3-a ]pyrazin-3-amines, and then elucidated their structures based on their ~1H-NMR, ^(13)C-NMR, ESI-HRMS, and nuclear Overhauser effect spectra.
基金financial support from the National Outstanding Youth Fund(No.29925204)
文摘An effective approach for the construction of the decalin ring skeleton of labdane diterpenoids was developed based on a key biomimetic cationic polyene cyclization of an epoxy allylsilane precursor. The synthetic approach demonstrated here would be useful in the enantioselective and diastereoselective total synthesis of natural labdane diterpenoids in general.
基金the National Natural Science Foundation of China(22201203).
文摘An atmospheric-oxygen-mediated four-component reaction was developed for the divergent synthesis of pyrazolo[1,5-a]pyrimidine and pyrazolo[3,4-b]pyridine derivatives from readily available alcohols and 3-aminopyrazoles.In this transformation,atmospheric oxygen serves as the green oxidant,promoting alcohols as equivalent aldehydes for the synthesis of four types of N-containing heterocycles(>40 examples).Remarkably,the transformation features metal-free and molecular diversity.
基金the National Natural Science Foundation of China (Grant No. 29872032) the Provincial Natural Science Foundation of Shaanxi Province (Grant No. FF982134).
文摘Muscone is a precious fragrant compound scarce in nature. Many attempts have been made to synthesize this unique natural product. In this work, the one-carbon unit transfer reaction of tetrahydrofolate coenzyme was initiated. Benzimidazolium salt was used as the tetrahydrofolate coenzyme model at formic acid oxidation level and di-Grignard reagent as the nucleophile to which one-carbon unit was transferred; the biomimetic synthesis of 2,15-hexade-canedione, a precursor of muscone, was successfully accomplished by using the addition-hydrolysis reaction of benzimidazolium salt with Grignard reagent. And an important useful method for the synthesis of muscone is provided.
基金grateful for financial support from the National Natural Science Foundation of China(grants 21722206,21672171)Financial support from the Scientific Fund of Northwest A&F University is also acknowledged.
文摘Halocyclization of olefinic substrate enables the establishment of cyclic skeletons via intramolecular halonium-induced nucleophilic addition,which has been well utilized as a practical strategy for constructing cyclic skeletons in natural product synthesis.Recently,the renaissance and rapid evolution of organocatalysis have accelerated the development of catalytic asymmetric halocyclization.In this context,natural product synthesis powered by catalytic asymmetric halocyclization has also achieved considerable progress in recent years.In some cases,these newly developed protocols enable more concise synthetic routes for accessing enantioenriched natural products.To this end,this review summarizes the applications of catalytic asymmetric halocyclization in natural product synthesis.
文摘Lycopodium alkaloids, a unique family of biologically important natural products isolated and characterized from various species of Lycopodium(sensu lato), have attracted extensive attention from chemists and pharmacists in the past three decades. Michael addition-based cyclization has been successfully employed as an elegant and efficient ring-construction protocol of constructing key cyclohexanone intermediates in the total synthesis of Lycopodium alkaloids. This mini-review chooses and summarizes several representative total syntheses of various Lycopodium alkaloids in which intramolecular Michael addition severed as the key methodology.
基金This work was supported by the National Natural Science Foundation of China(21572180)the Intergovernmental Science and Technology Cooperation and Exchange Program between China and Romania(43-24-20180510)the National College Students’Innovation and Entrepreneurship Training Program of China(S201910699286).
文摘To achieve head-to-tail cyclic peptides via the liquid-phase on-support cyclization and synergistic self-cleavage strategy,4,4’-bis(diphenylphosphinyloxyl)diphenyl ketoxime(BDKO)and 4-diphenyl phospho-loxy benzyl alcohol(DPBA)were designed and prepared as small-molecular supports of greener peptide synthesis.In the process of the BDKO(or DPBA)support assisted Boc strategy for liquid-phase peptide chain extension,the last amino acid at the N-terminus of the peptide chain ends with a Fmoc protected amino acid.
基金Project supported by the National Natural Science Foundation of China （Nos. 20872088, 21072126）, the Leading Academic Discipline Projects of Shanghai Municipal Education Commission （No. J50102） and the Graduated Student Innovation Fund of Shanghai University （No. SHUCX 112034）
文摘In the presence of Cu（OAc）2·H2O, a variety of 5-trifluoromethyl-2,4-disubstituted oxazoles were easily synthesized via t-BuOOH （TBHP）/I2-mediated tandem oxidative cyclization from readily available starting materials aryl methanamines and α-trifluoroacetyl-substituted ketones or esters under mild conditions, The mechanism was proposed.
基金the National Natural Science Foundation of China(22277082)Liaoning Province Education Administration of China(LJKQz2022236)+1 种基金Liaoning Provincial Foundation of Natural Science(2022-MS-245)China Postdoctoral Science Foundation(2022MD723807)for financial support.
文摘Comprehensive Summary An asymmetric synthesis of dihydrospirotryprostatin B was achieved in 15 steps(8 purifications)from L-tryptophan.The main feature of our synthetic strategy is the efficient construction of spirocyclic oxindole intermediate containing a chiral quaternary carbon center,involving the silica gel-mediated cyclization of tryptamine-ynamide and oxidation under neat conditions.
基金Financial support was provided by the State Key Laboratory of Pulp and Paper Engineering(No.2022PY01)the National Natural Science Foundation of China(Nos.22231002 and 21871095)the Key-Area Research and Development Program of Guangdong Province(No.2020B010188001)。
文摘Lignans have been established as a privileged scaffold in drug discovery,particularly in anticancer and antioxidant properties.Concise and efficient construction of lignans and their derivatives in a single operation holds great medicinal significance for structure-activity relationship studies yet remains challenging.Drawing inspiration from the biosynthesis of lignans,we present a general,high-step-economy palladium-catalyzed reaction that converts simple chemical feedstocks into dehydrodibenzylbutyrolactone lignans through the in-situ construction and coupling of two phenylpropanoid molecules.The diversity of organoboronic acids and the editability of enyne provide a powerful platform for the rapid construction of lignan libraries,featuring 82 lignans analogs,collective syntheses of 10 distinct lignan skeletons,and 13 hybrid molecules combining pharmacophore fragments with drug and derivatives.The subtle combination of phosphine ligands with quinones for switching chemoselectivity is vital to the success of this protocol.
基金supported by the National Key R&D Program of China(2023YFA1506700)NSFC(22071186,22071187,22101216,22271226,and 22371216)National Youth Talent Support Program.
文摘Comprehensive Summary.Nitrogen-containing bridged-heterocycles and indoles are key subunits of many natural products and pharmacologically active molecules.We herein present a bimetallic Cu/Ir catalyzed asymmetric allylation of ketimine esters and(E)-4-indolyl allyl carbonates followed by acid-promoted Pictet-Spengler cyclization sequences,enabling stereodivergent synthesis of chiral indole fused 9-azabicyclo[4.2.1]nonanes containing an eight-membered ring with one tertiary and two quaternary stereogenic centers.This one-pot sequential protocol features step economy,good substrate tolerance,and excellent stereoselective control.
基金This program was supported by National Key Basic Research Program(973)(No.G1998051125).
文摘A series of novel cyclic derivatives have been synthesized by utilizing a nickel powder mediated radical cyclization as the key step. The structures of the new compounds were confirmed by 1H-NMR and MS.
基金supported by grant from National Natural Science Foundation(No.20902109)Science & Technology Commission of Shanghai Municipality(No.08JC1405500)
文摘The first synthesis of the naturally occurring cyclic peptide euryjanicin B has been achieved.A general method was described to synthesize the cyclic peptide by a two-step solid-phase/solution synthesis strategy.All the amino acids in this study are L-configuration. The linear heptapeptide was assembled by standard Fmoc chemistry on solid-phase and subsequently cyclization was carried out by solution method.
文摘Terpenoids comprise the largest family of natural products and include various structurally different genus which play important roles in living organisms. Biosynthetically, diterpenoids are derived from （E,E,E）-geranylgeranyl diphosphate （GGPP）. From GGPP, diterpene cyclase catalyzes a sequence of carbocation- mediated cyclizations, rearrangements, and further oxidations, leading to a class of structurally unique ent-kaurenes, such as cafestol, gibberellin A3 and oridonin. According to the biosynthesis pathway of ent-kaurene, we designed a chiral acetal-enabled and SnCln-promoted biomimetic polyene cationic cyclization. With a following Birch reduc- tiort/alkylation cascade, a core skeleton of representative ent-kaurenes diterpenoids was completed.
