Diastereoselective catalytic hydrogenation of pyruvic acid esters, amides, and their Schiff bases has been well studied over a long period to show that proline is one of the most effective chiral auxiliaries. Proline ...Diastereoselective catalytic hydrogenation of pyruvic acid esters, amides, and their Schiff bases has been well studied over a long period to show that proline is one of the most effective chiral auxiliaries. Proline derivatives have been used as auxiliaries in the diastereoselective catalytic hydrogenation of pyruvamide Schiff bases. The diastereoselective hydrogenation resulted in up to a 78% enantiomeric excess of the amino acid derived from the hydrolysis of the dipeptide products. The chelation hypothesis explains the stereochemistry of the catalytic hydrogenation using (S)-proline esters in the amide moiety and the two chiral centers in the amide and Schiff base moieties.展开更多
The studies on the asymmetric alkylation of ester employing D-Isomannide and D-isosorbide as chiral auxiliaries were described. The diastereomeric excess of this reaction was up to 90%.
The photoinduced intramolecular meta-cycloaddition of bichromophores 1a-1d gave diastereoselectively two types of adducts 2a-2d and 3a-3d respectively. The observed stereochemistry of cycloaddition is rationalized in ...The photoinduced intramolecular meta-cycloaddition of bichromophores 1a-1d gave diastereoselectively two types of adducts 2a-2d and 3a-3d respectively. The observed stereochemistry of cycloaddition is rationalized in terms of hydrogen bond effect induced by the 4hydroxy group in the 5-phenylpent-1-ene skeleton.展开更多
The photoinduced intramolecular meta-cycloaddition of bichromophores 1a-1d gave diastereoselectively two types of adducts, 2a-2d and 3a-3d. respectively. The observed stereochemistry of cycloaddition was rationalized ...The photoinduced intramolecular meta-cycloaddition of bichromophores 1a-1d gave diastereoselectively two types of adducts, 2a-2d and 3a-3d. respectively. The observed stereochemistry of cycloaddition was rationalized in terms of hydrogen bond effect induced by the 3-hydroxy group in the 5-phenylpent-1-ene skeleton.展开更多
A bioinspired acid-triggered hemiacetalization/dehydration/[3 + 3]-type cycloaddition cascade process was disclosed, diastereoselectively furnishing furo[2,3-b]chromene skeleton under mild conditions. The viability of...A bioinspired acid-triggered hemiacetalization/dehydration/[3 + 3]-type cycloaddition cascade process was disclosed, diastereoselectively furnishing furo[2,3-b]chromene skeleton under mild conditions. The viability of this approach was demonstrated by syntheses of a series of furo[2,3-b]chromene and pyrano[2,3-b]chromene derivatives. The successful total syntheses of two lignan-phloroglucinol hybrids,hyperaspidinols A and B, exemplified the synthetic utility of our biomimetic methodology.展开更多
The copper-catalyzed directed dearomatization of indoles with the assistance of directing groups has been developed for the synthesis of 2,3-diazido indolines with good yields and excellent diastereoselectivities in a...The copper-catalyzed directed dearomatization of indoles with the assistance of directing groups has been developed for the synthesis of 2,3-diazido indolines with good yields and excellent diastereoselectivities in aqueous solution.The resultant 2,3-diazides can be smoothly converted to other functional groups,including vicinal diamines,triazoles and benzotriazoles,in a single step.展开更多
A diastereoselective method for the synthesis of chiral pyrrolidine and piperidine ring containing compounds was described. The protocol of bromination followed by aminocyclization furnishes an easily handled while hi...A diastereoselective method for the synthesis of chiral pyrrolidine and piperidine ring containing compounds was described. The protocol of bromination followed by aminocyclization furnishes an easily handled while highly efficient procedure for the intramolecular amidation of an isolated double bond. High diastereomeric excess was observed in this synthetic procedure.展开更多
An efficient water-based bismuth-mediated addition reaction of carbonyl compound with cyclic allylic halide was developed.The reactions proceeded smoothly in aqueous DMF in the presence of ammonium iodide to afford th...An efficient water-based bismuth-mediated addition reaction of carbonyl compound with cyclic allylic halide was developed.The reactions proceeded smoothly in aqueous DMF in the presence of ammonium iodide to afford the corresponding syn-homoallylic alcohols in moderate to good yields with excellent diastereoselectivities(>99:1 syn:anti).Reversal of product diastereoselectivity was observed when heteroaryl aldehyde possessing an adjacent chelating nitrogen atom was employed as substrate.展开更多
The diastereoselective photoreactions of Ir(III)-amine and Ir(III)-diamine complexes are observed in the presence of O2.TheɅ-[Ir(pq)_(2)(R-mapy)](PF_(6))(pq is 2-phenylquinoline and mapy is 2-(1-aminoethyl)pyridine)di...The diastereoselective photoreactions of Ir(III)-amine and Ir(III)-diamine complexes are observed in the presence of O2.TheɅ-[Ir(pq)_(2)(R-mapy)](PF_(6))(pq is 2-phenylquinoline and mapy is 2-(1-aminoethyl)pyridine)diastereomer is dehydrogenatively oxidized into imine complexɅ-[Ir(pq)_(2)(mapy-2H)](PF_(6))at room temperature,while theɅ-[Ir(pq)_(2)(S-mapy)](PF_(6))diastereomer occurs interligand C—N cross-coupling reaction at 60℃,affording a new tetradentate complexɅ-[Ir(pq)(S-pqpe)](PF_(6))(pqpe is 2-phenyl-N-(1-pyridin-2-yl)ethyl-quinolin-8-amine).The identical cases are also observed in diamine complexesɅ-[Ir(pq)_(2)(R,R-chda)](PF_(6))(chda is 1,2-diaminocyclohexane),Ʌ-[Ir(pq)_(2)(R,S-chda)](PF_(6)),andɅ-[Ir(pq)_(2)(S,S-chda)](PF_(6)),where the R configuration ligand is dehydrogenatively oxidized into imine,while the S configuration is retentive and the bound nitrogen atom is coupling to the C8 of pq ligand,affordingɅ-[Ir(pq)_(2)(chdi)](PF_(6))(chdi is 1,2-diiminocyclohexane),Ʌ-[Ir(pq)(S-pqchim)](PF_(6))(pqchim is N-(2-iminocyclohexyl)-2-phenyl-quinolin-8-amine),andɅ-[Ir(S,S-pqchda)](PF_(6))(pqchda is N',N”-bis(2-phenylquinolin-8-yl)cyclohexane-1,2-diamine),respectively.These provide a new and useful protocol for the synthesis of multidentate ligands in situ via the postcoordinated interligand-coupling strategy under mild conditions.展开更多
A hexafluoroisopropanol(HFIP)-catalyzed highly diastereoselective formal[4+2]cyclization between ortho-hydroxyphenyl para-quinone methides and difluoroenoxysilanes is developed.This tandem protocol provides a simple a...A hexafluoroisopropanol(HFIP)-catalyzed highly diastereoselective formal[4+2]cyclization between ortho-hydroxyphenyl para-quinone methides and difluoroenoxysilanes is developed.This tandem protocol provides a simple and straightforward approach to assemble diverse multiply functionalized difluorinated chromans with high to excellent diastereoselectivity by employing difluoroenoxysilane as a new C2 synthon.展开更多
The functionalized 1,10-dihydropyrrolo[1,2-a][1,10]phenanthroline derivatives were synthesized in good yields and with high diastereoselectivity by 1,3-dipolar cycloaddition reactions of N-phenacylphenanthrolinium bro...The functionalized 1,10-dihydropyrrolo[1,2-a][1,10]phenanthroline derivatives were synthesized in good yields and with high diastereoselectivity by 1,3-dipolar cycloaddition reactions of N-phenacylphenanthrolinium bromides or N-ethoxycarbonylmethylene phenanthrolinium bromide with various nitrostyrenes in acetonitrile at room temperature in the presence of triethvlamine,展开更多
A Sc(OTf)3-catalyzed[3+3]cycloaddition of 2,2’-diester aziridines withβ-(indol-2-yl)-α,β-unsaturated ketones was developed,affording polysubstituted tetrahydro-y-carbolines in single diastereoisomers in good to ex...A Sc(OTf)3-catalyzed[3+3]cycloaddition of 2,2’-diester aziridines withβ-(indol-2-yl)-α,β-unsaturated ketones was developed,affording polysubstituted tetrahydro-y-carbolines in single diastereoisomers in good to excellent yields.展开更多
(2R,4S,SS)-(+)-threo-5-(2,2-dicloroacetamido)-4-(4-nitrophenyl-2aryl-l,3dioxanes, were synthesized with high diastereoselectivity and good yields. The structuresofacetals were determined and the configurations were co...(2R,4S,SS)-(+)-threo-5-(2,2-dicloroacetamido)-4-(4-nitrophenyl-2aryl-l,3dioxanes, were synthesized with high diastereoselectivity and good yields. The structuresofacetals were determined and the configurations were confirmed by 2D-NMR (NOESY).展开更多
An efficient and stereoselective synthetic procedure for (3S,5S,6R)-3,7-dimethyl-5,6,7-trihydroxy-octanal derivative, the intermediate for synthetic of the HIV-active didemnaketals analogue. was developed via a series...An efficient and stereoselective synthetic procedure for (3S,5S,6R)-3,7-dimethyl-5,6,7-trihydroxy-octanal derivative, the intermediate for synthetic of the HIV-active didemnaketals analogue. was developed via a series of reactions from the natural (+)-Pulegone. In this approach, an efficient diastereoselective reaction of the epoxides 8 and 9 with PCC has been accomplished.展开更多
The reduction of TiCl4(THF)2 with Al in CH2Cl2 gave a green solution of [Ti2(μ-Cl)2Cl4· (THF)4] (1) which was found to promote the reductive homocoupling of aromatic aldehydes to yield symmetrical 1, 2-diols wit...The reduction of TiCl4(THF)2 with Al in CH2Cl2 gave a green solution of [Ti2(μ-Cl)2Cl4· (THF)4] (1) which was found to promote the reductive homocoupling of aromatic aldehydes to yield symmetrical 1, 2-diols with high diasterepselectivities.展开更多
Aldols from aliphatic aldehydes had been synthesized enantioselectively using Singh’s catalyst. Self and crossed aldol reactions with several linear aldehydes were performed.
Modest to high diastereoselectivites have been observed in the conjugate addition of functionalized alcohols to chiral (E)-nitroalkene 1 depending on the presence of metal catalysts at low tempertwre. The resultS indi...Modest to high diastereoselectivites have been observed in the conjugate addition of functionalized alcohols to chiral (E)-nitroalkene 1 depending on the presence of metal catalysts at low tempertwre. The resultS indicated that the anti-form had been preferred in all cases.展开更多
A novel strategy was developed for the asymmetric synthesis of fluorinated vicinal diamines.Deprotonation of N-(diphenylmethylene)-benzylamines under base,followed by asymmetric nucleophilic addition to N-tert-butanes...A novel strategy was developed for the asymmetric synthesis of fluorinated vicinal diamines.Deprotonation of N-(diphenylmethylene)-benzylamines under base,followed by asymmetric nucleophilic addition to N-tert-butanesulfinylfluoroacetaldimines,a pair of diastereomeric isomers were afforded.The diastereomeric isomers can be easily separated from each other by silica gel column chromatography.The absolute steric configuration of two isomers was confirmed by single crystal X-ray diffraction analyses.The proposed mechanism revealed that the configuration of the carbon next to tert-butanesulfinyl was well controlled to be R by the chiral auxiliary.展开更多
基金The project is generously supported by the National Natural Science Foundation of China (Grant No. 29972002 20172002)+1 种基金 the Trans-Century Training Programme Foundation for the Talents by Ministry of Education and Bayer Co. Ltd (Germany). We thank Dr
文摘Diastereoselective catalytic hydrogenation of pyruvic acid esters, amides, and their Schiff bases has been well studied over a long period to show that proline is one of the most effective chiral auxiliaries. Proline derivatives have been used as auxiliaries in the diastereoselective catalytic hydrogenation of pyruvamide Schiff bases. The diastereoselective hydrogenation resulted in up to a 78% enantiomeric excess of the amino acid derived from the hydrolysis of the dipeptide products. The chelation hypothesis explains the stereochemistry of the catalytic hydrogenation using (S)-proline esters in the amide moiety and the two chiral centers in the amide and Schiff base moieties.
文摘The studies on the asymmetric alkylation of ester employing D-Isomannide and D-isosorbide as chiral auxiliaries were described. The diastereomeric excess of this reaction was up to 90%.
文摘The photoinduced intramolecular meta-cycloaddition of bichromophores 1a-1d gave diastereoselectively two types of adducts 2a-2d and 3a-3d respectively. The observed stereochemistry of cycloaddition is rationalized in terms of hydrogen bond effect induced by the 4hydroxy group in the 5-phenylpent-1-ene skeleton.
文摘The photoinduced intramolecular meta-cycloaddition of bichromophores 1a-1d gave diastereoselectively two types of adducts, 2a-2d and 3a-3d. respectively. The observed stereochemistry of cycloaddition was rationalized in terms of hydrogen bond effect induced by the 3-hydroxy group in the 5-phenylpent-1-ene skeleton.
基金supported financially by the National Natural Science Foundation of China (Nos.81773602,21901049 and 21801032)Natural Science Foundation of Guangdong Province (No.2019A1515011694)+2 种基金Guangdong Special Support Program (No.2017TQ04R599)Youth Innovation Promotion Association of CAS (No.2020342)Guangxi Natural Science Foundation (Nos.2018GXNSFBA050015 and AD19245004)。
文摘A bioinspired acid-triggered hemiacetalization/dehydration/[3 + 3]-type cycloaddition cascade process was disclosed, diastereoselectively furnishing furo[2,3-b]chromene skeleton under mild conditions. The viability of this approach was demonstrated by syntheses of a series of furo[2,3-b]chromene and pyrano[2,3-b]chromene derivatives. The successful total syntheses of two lignan-phloroglucinol hybrids,hyperaspidinols A and B, exemplified the synthetic utility of our biomimetic methodology.
基金the National Natural Science Foundation of China(Nos.21472172,21272212)Natural Science Foundation of Zhejiang Province(No.LY17B060009)。
文摘The copper-catalyzed directed dearomatization of indoles with the assistance of directing groups has been developed for the synthesis of 2,3-diazido indolines with good yields and excellent diastereoselectivities in aqueous solution.The resultant 2,3-diazides can be smoothly converted to other functional groups,including vicinal diamines,triazoles and benzotriazoles,in a single step.
基金Project supported by the National Natural Science Foundation of China (No. 20272049).
文摘A diastereoselective method for the synthesis of chiral pyrrolidine and piperidine ring containing compounds was described. The protocol of bromination followed by aminocyclization furnishes an easily handled while highly efficient procedure for the intramolecular amidation of an isolated double bond. High diastereomeric excess was observed in this synthetic procedure.
基金financial support from Nanjing Tech University(Start-up Grant No.39837118)Yancheng Teachers UniversityNanjing Forestry University。
文摘An efficient water-based bismuth-mediated addition reaction of carbonyl compound with cyclic allylic halide was developed.The reactions proceeded smoothly in aqueous DMF in the presence of ammonium iodide to afford the corresponding syn-homoallylic alcohols in moderate to good yields with excellent diastereoselectivities(>99:1 syn:anti).Reversal of product diastereoselectivity was observed when heteroaryl aldehyde possessing an adjacent chelating nitrogen atom was employed as substrate.
基金the financial support from the National Natural Science Foundation of China(grant no.21971266).
文摘The diastereoselective photoreactions of Ir(III)-amine and Ir(III)-diamine complexes are observed in the presence of O2.TheɅ-[Ir(pq)_(2)(R-mapy)](PF_(6))(pq is 2-phenylquinoline and mapy is 2-(1-aminoethyl)pyridine)diastereomer is dehydrogenatively oxidized into imine complexɅ-[Ir(pq)_(2)(mapy-2H)](PF_(6))at room temperature,while theɅ-[Ir(pq)_(2)(S-mapy)](PF_(6))diastereomer occurs interligand C—N cross-coupling reaction at 60℃,affording a new tetradentate complexɅ-[Ir(pq)(S-pqpe)](PF_(6))(pqpe is 2-phenyl-N-(1-pyridin-2-yl)ethyl-quinolin-8-amine).The identical cases are also observed in diamine complexesɅ-[Ir(pq)_(2)(R,R-chda)](PF_(6))(chda is 1,2-diaminocyclohexane),Ʌ-[Ir(pq)_(2)(R,S-chda)](PF_(6)),andɅ-[Ir(pq)_(2)(S,S-chda)](PF_(6)),where the R configuration ligand is dehydrogenatively oxidized into imine,while the S configuration is retentive and the bound nitrogen atom is coupling to the C8 of pq ligand,affordingɅ-[Ir(pq)_(2)(chdi)](PF_(6))(chdi is 1,2-diiminocyclohexane),Ʌ-[Ir(pq)(S-pqchim)](PF_(6))(pqchim is N-(2-iminocyclohexyl)-2-phenyl-quinolin-8-amine),andɅ-[Ir(S,S-pqchda)](PF_(6))(pqchda is N',N”-bis(2-phenylquinolin-8-yl)cyclohexane-1,2-diamine),respectively.These provide a new and useful protocol for the synthesis of multidentate ligands in situ via the postcoordinated interligand-coupling strategy under mild conditions.
基金the financial support from the Natural Science Foundation of Zhejiang Province(No.LQ20B020005)Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang(No.2019R01005)Joint Fund of Zhejiang Provincial Natural Science Foundation(No.LTZ21B020001)。
文摘A hexafluoroisopropanol(HFIP)-catalyzed highly diastereoselective formal[4+2]cyclization between ortho-hydroxyphenyl para-quinone methides and difluoroenoxysilanes is developed.This tandem protocol provides a simple and straightforward approach to assemble diverse multiply functionalized difluorinated chromans with high to excellent diastereoselectivity by employing difluoroenoxysilane as a new C2 synthon.
基金the National Natural Science Foundation of China,the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘The functionalized 1,10-dihydropyrrolo[1,2-a][1,10]phenanthroline derivatives were synthesized in good yields and with high diastereoselectivity by 1,3-dipolar cycloaddition reactions of N-phenacylphenanthrolinium bromides or N-ethoxycarbonylmethylene phenanthrolinium bromide with various nitrostyrenes in acetonitrile at room temperature in the presence of triethvlamine,
基金supported by the National Natural Science Foundation of China(No.21772038)the China Postdoctoral Science Foundation(No.2018M632037)。
文摘A Sc(OTf)3-catalyzed[3+3]cycloaddition of 2,2’-diester aziridines withβ-(indol-2-yl)-α,β-unsaturated ketones was developed,affording polysubstituted tetrahydro-y-carbolines in single diastereoisomers in good to excellent yields.
文摘(2R,4S,SS)-(+)-threo-5-(2,2-dicloroacetamido)-4-(4-nitrophenyl-2aryl-l,3dioxanes, were synthesized with high diastereoselectivity and good yields. The structuresofacetals were determined and the configurations were confirmed by 2D-NMR (NOESY).
文摘An efficient and stereoselective synthetic procedure for (3S,5S,6R)-3,7-dimethyl-5,6,7-trihydroxy-octanal derivative, the intermediate for synthetic of the HIV-active didemnaketals analogue. was developed via a series of reactions from the natural (+)-Pulegone. In this approach, an efficient diastereoselective reaction of the epoxides 8 and 9 with PCC has been accomplished.
文摘The reduction of TiCl4(THF)2 with Al in CH2Cl2 gave a green solution of [Ti2(μ-Cl)2Cl4· (THF)4] (1) which was found to promote the reductive homocoupling of aromatic aldehydes to yield symmetrical 1, 2-diols with high diasterepselectivities.
文摘Aldols from aliphatic aldehydes had been synthesized enantioselectively using Singh’s catalyst. Self and crossed aldol reactions with several linear aldehydes were performed.
文摘Modest to high diastereoselectivites have been observed in the conjugate addition of functionalized alcohols to chiral (E)-nitroalkene 1 depending on the presence of metal catalysts at low tempertwre. The resultS indicated that the anti-form had been preferred in all cases.
基金the Innovation Program of Shanghai Municipal Education Commission,China(No.13ZZ047)the Fundamental Research Funds for the Central Universities,China(No.2232015D3-13)
文摘A novel strategy was developed for the asymmetric synthesis of fluorinated vicinal diamines.Deprotonation of N-(diphenylmethylene)-benzylamines under base,followed by asymmetric nucleophilic addition to N-tert-butanesulfinylfluoroacetaldimines,a pair of diastereomeric isomers were afforded.The diastereomeric isomers can be easily separated from each other by silica gel column chromatography.The absolute steric configuration of two isomers was confirmed by single crystal X-ray diffraction analyses.The proposed mechanism revealed that the configuration of the carbon next to tert-butanesulfinyl was well controlled to be R by the chiral auxiliary.