NianFei Yang

Name: 阳年发; NianFei Yang

Organization: Xiangtan University

Department: Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry

Title: Professor

TOPICS

Polymer

Photopolymerization

Organic Chemistry

Asymmetric Synthesis Diels Alder Reaction

Chemicals
References

Asymmetric Hydrogenation of Cyclic Imines of Benzoazepines and Benzodiazepines with Chiral, Cationic Ruthenium–Diamine Catalysts

Co-reporter:Zhusheng Yang;Ziyuan Ding;Fei Chen;Yan-Mei He;Nianfa Yang;Qing-Hua Fan

European Journal of Organic Chemistry 2017 Volume 2017(Issue 14) pp:1973-1977

Publication Date(Web):2017/04/10

DOI:10.1002/ejoc.201700236

A method for the highly enantioselective hydrogenation of diverse seven-membered N-containing heterocycles, including 2,4-diaryl-3H-benzo[b]azepines, racemic 2,2,4-trisubstituted 2,3-dihydrobenzo[b][1,4]diazepines, and 4-substituted 1H-benzo[b][1,4]diazepin-2(3H)-ones by using chiral, cationic ruthenium–diamine catalysts was developed. Reversal of enantioselectivity was observed for all of these substrates simply by changing the achiral counteranion of the catalyst. This method thus provided facile access to both enantiomers of these optically pure seven-membered heterocycles.

Synthesis and Properties of Optically Active Helical Polyethers Bearing Indole or Carbazole Derivatives

Co-reporter:Chunhui Zhao;Kunbing Ouyang;Nianfa Yang;Jin Zhang

Macromolecular Research 2016 Volume 24( Issue 5) pp:393-399

Publication Date(Web):2016 May

DOI:10.1007/s13233-016-4057-x

Six optically active oxide propane monomers (1m-6m) were synthesized in a very facile way. The monomers were polymerized using potassium hydroxide (KOH) as an initiator to afford the corresponding polyethers (1p-6p). The polyether (R)-1p (specific rotation, [α]36525=+331) exhibited optical rotation as large as fourfold that of the monomer (R)-1m ([α]36525=-10). The specific optical rotation, circular dichroism (CD) and ultraviolet (UV)-visible spectra data showed that the obtained polymers can keep a prevailing helicity of the backbone in solution.

Chiral fluorescence polyethers based on BINOL for enantioselective recognition of phenylalanine anion

Co-reporter:Chunhui Zhao, Kunbing Ouyang, Jin Zhang, Nianfa Yang

Polymer 2016 Volume 93() pp:9-13

Publication Date(Web):14 June 2016

DOI:10.1016/j.polymer.2016.04.013

•BINOL-based fluorescence sensors with two chiral moieties were reported.•Enantioselective recognition was conducted in aqueous solution of THF/H2O.•Configurations of both BINOL and ECH affect the selectivity.•The value of enantiomeric fluorescence difference ratio (ef) reached to 6.29.Series of polyethers with different configurations were synthesized from chiral BINOL and optical epichlorohydrin. The optical behavior of the obtained polyethers is evaluated with specific optical rotation, UV–vis spectroscopy, circular dichroism (CD) and fluorescence spectroscopy. Thermogravimetric analysis (TGA) reveals the polyethers a good thermal stability. The fluorescence responses of the chiral polyethers on chiral phenylalanine anion were investigated. The sensors (S,S)-4 and (R,R)-4 showed high enantioselective fluorescent sensing ability to phenylalanine anion. The value of enantiomeric fluorescence difference ratio (ef) reached to 6.29.Series of polyethers with different configurations were synthesized from chiral BINOL and optical epichlorohydrin. The sensors (S,S)-4 and (R,R)-4 showed high enantioselective fluorescent sensing ability to phenylalanine anion. The value of enantiomeric fluorescence difference ratio (ef) reached to 6.29.

Optically active helical vinyl polymers via radical polymerization of (S)-3-vinyl-2,2-bisalkoxy-1,1-binaphthyl

Co-reporter:Yehui Chen;Guochang Qin;Liwen Yang;Nianfa Yang;Zhusheng Yang

Polymer International 2015 Volume 64( Issue 7) pp:907-914

Publication Date(Web):

DOI:10.1002/pi.4864

Abstract

(S)-3-Vinyl-2,2′-bisalkoxy-1,1′-binaphthyl (3) was synthesized via the Wittig reaction. Radical polymerization of all the monomers can take place smoothly in the temperature region tested. These polymers (poly-3) showed very large specific optical rotations which were four times as large as those of the corresponding monomers 3. Poly-3 displayed optical rotations and Cotton effects in the UV−visible absorption region of side groups which were different from the corresponding monomers 3 and the model compounds (S)-3-ethyl-2,2′-bisalkoxy-1,1′-binaphthyl (4). These facts imply the formation of helicity of the main chain and the helical conformations were quite stable demonstrated by the unchanged pattern of temperature variable circular dichroism spectra. © 2015 Society of Chemical Industry

Optically Active Helical Poly[(S)-3-vinyl-2,2-dihydroxy-1,1-binaphthyl]: New Ligand for Asymmetric Addition of Diethylzinc to Aryl Aldehyde

Co-reporter:Yehui Chen;Guochang Qin;Liwen Yang ;Nianfa Yang

Chinese Journal of Chemistry 2015 Volume 33( Issue 4) pp:463-466

Publication Date(Web):

DOI:10.1002/cjoc.201400819

Abstract

Poly[(S)-3-vinyl-2,2′-dihydroxy-1,1′-binaphthyl] (L*) was obtained by taking off the protecting groups of poly[(S)-3-vinyl-2,2′-bis(methoxymethoxy)-1,1′-binaphthyl] (poly-1). L* was proved to keep a stable helical conformation in solution. The application of helical L* in the asymmetric addition of diethylzinc to aldehydes has been studied. The catalytic system employing 10 mol% of L* and 150 mol% of Ti(OⁱPr)₄ was found to promote the addition of diethylzinc to a wide range of aromatic aldehydes, giving up to 99% enantiomeric excess (ee) and up to 93% yield of the corresponding secondary alcohol at 0°C. The chiral polymer can be easily recovered and reused without loss of catalytic activity as well as enantioselectivity.

Asymmetric Borane Reduction of Prochiral Ketones Catalyzed By Helical Poly[(S)-3-vinyl-2,2'-dihydroxy-1,1'-binaphthyl]

Co-reporter:Guochang Qin;Yehui Chen;Liwen Yang;Nianfa Yang;Zhusheng Yang

Chirality 2015 Volume 27( Issue 7) pp:422-424

Publication Date(Web):

DOI:10.1002/chir.22459

Abstract

The application of helical poly[(S)-3-vinyl-2,2'-dihydroxy-1, 1'-binaphthyl] (L*) in the asymmetric borane reduction of prochiral ketones was studied. The results showed that L* had excellent catalytic activity as well as enantioselectivity, giving up to 96% yield and up to 99% enantiomeric excess (ee) of the corresponding secondary alcohol at 25 °C. Moreover, L* can be easily recovered and reused without loss of catalytic activity. Chirality 27:422–424, 2015. © 2015 Wiley Periodicals, Inc.

Helix-sense-selective radical polymerization of (S)-6-acryloyl-2,2′-bisalkoxy-1,1′-binaphthyl

Co-reporter:Yehui Chen;Liwen Yang;Nianfa Yang;Jingyi Yan;Zhusheng Yang

Polymer Bulletin 2015 Volume 72( Issue 12) pp:3183-3190

Publication Date(Web):2015 December

DOI:10.1007/s00289-015-1460-y

A series of (S)-6-acryloyl-2,2′-bisalkoxy-1,1′-binaphthyl 1 were radically polymerized to obtain polymers. The optical rotation and the circular dichroism (CD) signal intensity of the radically polymerized poly-1 were close to that of the anionically polymerized poly-1 indicating that the radically polymerized poly-1 should adopt stable preferred-handed helical conformation in solution just as the anionically polymerized poly-1.

Investigation of catalytic activity and catalytic mechanism of chiral amino diol tridentate ligands in the asymmetric addition of aldehydes in the present of methyllithium reagent

Co-reporter:An-Lin Zhang, Li-Wen Yang, Nian-Fa Yang, Da-Cai Liu

Journal of Organometallic Chemistry 2014 Volume 768() pp:50-55

Publication Date(Web):1 October 2014

DOI:10.1016/j.jorganchem.2014.06.012

•Several chiral amino diol tridentate ligands show good enantioselectivities.•Increase in the bulkiness of the achiral auxiliary of ligands increased the enantioselectivity.•The 1H NMR spectrum reveal the formation of mono-metallic and hexa-coordinated titanium complex.Several highly modular chiral amino diol tridentate ligands were found to be effective for the asymmetric alkylation reaction of aromatic aldehydes in the presence of methyllithium reagent, providing up to 96% ee values and up to 94% yields under relatively mild conditions. The investigation of the catalytic activity of these ligands shows a correlation of enantioselectivities of ligands with steric properties of substituent N-alkyl and nucleophilic Li-alkyl. With the addition of Ti(O-i-Pr)4 to the ligand 3c, the 1H NMR spectrum reveals a hexa-coordinate Ti transition state complex with only one Ti metal center generated in solution.Several highly modular chiral amino diol tridentate ligands were found to be effective for the asymmetric alkylation reaction of aromatic aldehydes in the presence of methyllithium reagent, providing up to 96% ee values and up to 94% yields under relatively mild conditions.

Helical Poly(,-unsaturated ketone) with Bulky Pendant of Binaphthyl from Anionic Polymerization of (()-Menthyl (S)-6-Acrylyl-2-methyloxy-1,1-binaphthalene-2-carboxylate

Co-reporter:Yehui Chen;Liwen Yang;Nianfa Yang;Zhusheng Yang ;Jin Zhang

Chinese Journal of Chemistry 2014 Volume 32( Issue 3) pp:241-247

Publication Date(Web):

DOI:10.1002/cjoc.201400011

Abstract

((−)-Menthyl (S)-6′-acrylyl-2′-methyloxy-1,1′-binaphthalene-2-carboxylate (3) was synthesized and anionically polymerized using n-BuLi as an initiator in toluene. The monomer 3 was levorotatory and had an [α]_D²⁵ value of −72.4, but its corresponding polymer poly-3 was dextrorotatory and showed an [α]_D²⁵ value of +162.0. Poly-3 was confirmed to exist in the form of one-handed helical structure in solution by means of comparing the specific optical rotation and the CD spectra with that of 3 and the model compounds such as (−)-menthyl (S)-6′-propionyl-2′-methyloxy-1,1′-binaphthalene-2-carboxylate 2b and (−)-menthyl (S)-6′-heptanoyl-2′-methyloxy-1,1′-binaphthalene-2-carboxylate 2c. This conclusion was also confirmed by the fact that the g-value of poly-3 is about 11 times of that of monomer 3.

The synthesis of chiral amino diol tridentate ligands and their enantioselective induction during the addition of diethylzinc to aldehydes

Co-reporter:An-lin Zhang, Li-wen Yang, Nian-fa Yang, Yan-ling Liu

Tetrahedron: Asymmetry 2014 Volume 25(Issue 4) pp:289-297

Publication Date(Web):28 February 2014

DOI:10.1016/j.tetasy.2013.11.007

A series of C2-symmetric chiral amino diol tridentate ligands 3a–g were prepared from achiral bulky organolithiums, achiral bulky primary amines, and optically active epichlorohydrin (ECH). The prepared C2-symmetric chiral amino diol tridentate ligands were capable of inducing enantioselectivity in the model reaction of aromatic and aliphatic aldehydes with diethylzinc with an ee of up to 96%. The enantioselectivity can be modulated by adjusting the steric hindrance of the achiral reagents employed in the synthesis of the chiral ligand. The configuration of the addition product depended on the configuration of the amino diol ligands, which can be simply controlled as desired by using the ECH with the desired configuration during the preparation of the ligand.Benzyl bis[3-(9-ethylfluoren-9-yl)-2(S)-hydroxypropyl] amineC43H45NO2[α]D20=+106.4 (c 1, THF)Source of chirality: (S)-9-ethylfluoren-9-yl propene oxideAbsolute configuration: (S,S)Benzyl bis[3-triphenylmethyl-2(R)-hydroxypropyl] amineC51H49NO2[α]D20=+78.8 (c 1, THF)Source of chirality: (R)-4,4,4-triphenylbutene oxideAbsolute configuration: (R,R)Benzyl bis[3-triphenylmet hyl-2(S)-hydroxypropyl] amineC51H49NO2[α]D20=-78.0 (c 1,THF)Source of chirality: (S)-4,4,4-triphenylbutene oxideAbsolute configuration: (S,S)n-Butyl bis[3-triphenylmethyl-2(S)-hydroxypropyl] amineC48H51NO2[α]D20=-70.1 (c 1, THF)Source of chirality: (S)-4,4,4-triphenylbutene oxideAbsolute configuration: (S,S)Benzyl bis[3-(1-pentyldibenzo[a,e]suber-1-yl)-2(S)-hydroxypropyl] amineC53H65NO2[α]D20=+66.8 (c 1, CH2Cl2)Source of chirality: (S)-1-pentyldibenzo[a,e]suber-1-ylpropene oxideAbsolute configuration: (S,S)Cyclohexyl bis[3-triphenylmethyl-2(S)-hydroxypropyl] amineC50H53NO2[α]D20=-72.6 (c 1, THF)Source of chirality: (S)-4,4,4-triphenylbutene oxideAbsolute configuration: (S,S)tert-Butyl bis[3-triphenylmethyl-2(S)-hydroxypropyl] amineC48H51NO2[α]D20=-82.55 (c 1, THF)Source of chirality: (S)-4,4,4-triphenylbutene oxideAbsolute configuration: (S,S)Diphenylmethyl bis[3-triphenylmethyl-2(S)-hydroxypropyl] amineC57H53NO2[α]D20=-69.4 (c 1, THF)Source of chirality: (S)-4,4,4-triphenylbutene oxideAbsolute configuration: (S,S)

Synthesis and characterization of optically active helical poly(α, β-unsaturated ketone) with bulky pendant of binaphthyl

Co-reporter:Yehui Chen;Liwen Yang;Nianfa Yang;Jingyi Yan;Zhusheng Yang

Polymer Bulletin 2014 Volume 71( Issue 10) pp:2507-2521

Publication Date(Web):2014 October

DOI:10.1007/s00289-014-1204-4

The synthesis and chiroptical properties of a novel optically active helical polymers, poly[(S)-6-acryloyl-2,2′-bisalkoxy-1,1′-binaphthyl] (poly-3), were reported. All the monomers readily underwent anionic polymerization to yield the polymers displaying optical rotations and Cotton effects in the UV–vis absorption region of side groups distinct to monomers (3) and the corresponding model compounds such as (S)-6-propionyl-2,2′-bisalkoxy-1,1′-binaphthyl (4) and (S)-6-heptanoyl-2,2′-bisalkoxy-1,1′-binaphthyl (5), implying the formation of main-chain chirality, most probable helicity. Their helical conformations were quite stable as revealed by the almost unchanged chiroptical properties measured at different temperatures.

Single-handed helical poly-(α, β-unsaturated ketone) synthesized via anionic polymerization of (S)-2′-methyloxy-2-acrylyl-1,1′-binaphthyl

Co-reporter:Ye Hui Chen;Li Wen Yang;Nian Fa Yang;Jian Zhang

Macromolecular Research 2014 Volume 22( Issue 3) pp:236-239

Publication Date(Web):2014 March

DOI:10.1007/s13233-014-2057-2

Optically active helical vinyl polymers via helix-sense-selective anionic polymerization of (S)-3-vinyl-2,2′-bis(methoxymethoxy)-1,1′-binaphthyl

Co-reporter:Ye-Hui Chen, Jin Zhang, Li-Wen Yang, Nian-Fa Yang, Zhu-Sheng Yang

Polymer 2014 Volume 55(Issue 16) pp:3666-3671

Publication Date(Web):5 August 2014

DOI:10.1016/j.polymer.2014.06.033

•(S)-3-Vinyl-2,2′-bis(methoxymethoxy)-1,1′-binaphthyl 2 was synthesized and anionically polymerized.•Poly-2 exhibited optical rotation as large as fourfold that of the monomer.•The CD spectrum of poly-2 show intensive Cotton effects, implying the formation of main chain chirality, most probable helicity.•The helical conformation of poly-2 was stable and insensitive to temperature variation.A novel vinyl monomer, (S)-3-vinyl-2,2′-bis(methoxymethoxy)-1,1′-binaphthyl 2, was synthesized and underwent helix-sense-selective anionic polymerization to obtain helical polymers with an excess screw sense. The polymer ([α]36525 = −1610.0°) exhibited optical rotation as large as fourfold that of the monomer ([α]36525 = −356.0°). Poly-2 was confirmed to keep a prevailing helicity of backbone in solution by means of comparing the specific optical rotation, the CD and UV–vis spectra with that of monomer 2 and the model compound such as (S)-3-ethyl-2,2′-bis(methoxymethoxy)-1,1′-binaphthyl 3. The helical conformation of poly-2 was stable and insensitive to temperature variation. The excess value of one-handed helicity of poly-2 decreased with the increase of polymerization temperature.

Helix-sense-selective anionic polymerization of (S)-2’-methyloxy-2-vinyl-1,1’-binaphthyl

Co-reporter:Ye Hui Chen;Li Wen Yang;Nian Fa Yang;Zhu Sheng Yang

Macromolecular Research 2014 Volume 22( Issue 11) pp:1152-1155

Publication Date(Web):2014 November

DOI:10.1007/s13233-014-2181-z

Synthesis of chiral bisacylphosphine oxides and their application as initiators in helix-sense-selective photopolymerization

Co-reporter:Jia-An Zhang;Nian-Fa Yang;Li-Wen Yang;Shi Wu;Ye-Hui Chen

Macromolecular Research 2013 Volume 21( Issue 6) pp:641-648

Publication Date(Web):2013 June

DOI:10.1007/s13233-013-1077-7

Synthesis, characterization, polymerization of optically active terminal epoxides and episulfides bearing bulky groups

Co-reporter:Yun-kai Sun;Jin Zhang;Hui-jun Liu;Li He

Chemical Research in Chinese Universities 2013 Volume 29( Issue 2) pp:239-244

Publication Date(Web):2013 April

DOI:10.1007/s40242-013-2299-0

A simple and efficient protocol was developed for the syntheses of optically active epoxides(2a–2d) via the reactions of epichlorohydrin with organometallic reagents with steric hindrance at low temperature. On this basis, episulfides(3a–3d) were obtained with high e.e. values by the reaction of the corresponding epoxides with NH4SCN. The configuration of thiiranes was opposite to that of the corresponding epoxides. Then, epoxides 2a–2d were anionically polymerized and the poly-R-2a(or poly-S-2a) was proved to keep a stable one-handed helical conformation in solution. The oligomers[degree of polymerization(DP)=2–5] were obtained when the thiiranes(3a, 3b and 3c) were used to polymerize.

Enantioselective inductivity of optically active helical poly[3-(9-alkylfluoren-9-yl)propylene oxide]s in the addition of methyllithium to aldehydes

Co-reporter:Changwei Huang, Nianfa Yang, Anlin Zhang, Liwen Yang

Polymer 2012 Volume 53(Issue 16) pp:3514-3519

Publication Date(Web):19 July 2012

DOI:10.1016/j.polymer.2012.05.054

Optically active helical poly[(R or S)-3-(9-alkylfluoren-9-yl)propene oxide]s (poly-AFPOs) were used to induce the enantioselective addition of methyllithium to aldehydes. The addition of methyllithium to 4-methoxybenzaldehyde gave the highest enantioselectivity (88% ee) under the inducement of poly-AFPOs. Poly-AFPOs could be recovered simply by pouring the reaction mixture into methanol in the end of the reaction and separating the precipitated polymer via filtration. The recovered poly-AFPOs could be reused for many times to induce the enantioselective addition of methyllithium to aldehyde without losing their enantioselective inducement ability. The investigation of the optical rotation and the MALDI-ToF MS confirmed that, in the enantioselective addition induced by poly-AFPOs, the lithium cation was embedded in the hole of the helical column of poly-AFPOs, leaving the negative methyl ion outside the one-handed helical column. The methyl anion abutted tightly against the helical polymer and acquired a chiral environment. It was this helically chiral environment that resulted in the enantioselective inducement of the addition reaction.

Dicyanostilbene-derived two-photon fluorescence dyes with large two-photon absorption cross sections

Co-reporter:Chibao Huang, Changhua Lin, Anxiang Ren, Nianfa Yang

Journal of Molecular Structure 2011 Volume 1006(1–3) pp:91-95

Publication Date(Web):14 December 2011

DOI:10.1016/j.molstruc.2011.08.016

Four dicyanostilbene-derived two-photon fluorescence (TPF) dyes were synthesized as the model compounds to systematically study the effect of the dicyano and the terminal substituent on the two-photon absorption (TPA). These four compounds (DSO, DCY, DTO and DPH) exhibit very large two-photon absorption cross sections (δ). DCY (A–π–A) with the terminal cyano group has especially high fluorescence quantum yield (0.71) and relatively large δ (1480 GM), while DPH (D–π–A) with the substitutedamino group at its terminus possesses the largest δ (2800 GM) and the longest emission wavelength (620 nm). The idealest terminal substituent should not be the alkoxy group but the substitutedamino group. This class of dicyanostilbene dyes possess small molecule size, large δ (830–2800 GM), long-wavelength emission (459−620 nm) and large Stokes shift (80−206 nm), and are ideal chromophores for TPF labels and probes.

Optically active helical polymer from radical polymerization of menthyl vinyl ketone

Co-reporter:Shi Wu;Nianfa Yang;Yanling Liu;Jing Cao;Hai Hu;Yunkai Sun;Ji Liu

Journal of Polymer Science Part A: Polymer Chemistry 2011 Volume 49( Issue 1) pp:293-299

Publication Date(Web):

DOI:10.1002/pola.24452

Abstract

Menthyl vinyl ketone (MVK) was radically polymerized to obtain a polymer with excess of one-handed helical sense. Like as the anionically polymerized poly-MVK, the radically polymerized poly-MVK also kept stable one-handed helical conformation in solvent. The optical rotation and the circular dichroism signal intensity of the radically polymerized poly-MVK were larger than that of the anionically polymerized poly-MVK. The molecular weight of the radically polymerized poly-MVK was much larger than that of the THF-soluble part of the anionically polymerized poly-MVK. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010

A novel type of optically active helical polymers: Synthesis and characterization of poly(,-unsaturated ketone)

Co-reporter:Shi Wu;Nianfa Yang;Liwen Yang;Jing Cao ;Ji Liu

Journal of Polymer Science Part A: Polymer Chemistry 2010 Volume 48( Issue 6) pp:1441-1448

Publication Date(Web):

DOI:10.1002/pola.23915

Abstract

New α,β-unsaturated ketone monomers, menthyl vinyl ketone (MVK), and 1-menthylbut-3-en-2-one (MBEK) were synthesized. The monomers were polymerized using butyllithium as an initiator. The polymer derived from MVK (poly-MVK) had a tremendous specific optical rotation [α], which was as 32 times large as that of its monomer MVK. Poly-MVK was confirmed to keep a prevailing helicity of backbone in solution by means of comparing the specific optical rotation and the CD spectra with that of MVK and the model compound such as ethyl menthyl ketone (EMK) and n-hexyl menthyl ketone (n-HMK). This conclusion was also confirmed by the fact that the specific optical rotation and the CD signal intensity of poly-MBEK were not enough large due to backbone flexibility caused by the effective isolation of the main chain from the bulky menthyl. The excess value of one-handed helicity of poly-MVK decreased with the increase of polymerization temperature. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1441–1448, 2010

Single-handed helical polyethers synthesized via anionic polymerization of optically active 3-(9-alkylfluoren-9-yl)propene oxides

Co-reporter:Yunkai Sun, Nianfa Yang, Ji Liu, Jing Cao, Hang Gong

Polymer 2010 Volume 51(Issue 24) pp:5712-5718

Publication Date(Web):12 November 2010

DOI:10.1016/j.polymer.2010.10.017

A series of optically active 3-(9-alkylfluoren-9-yl)propene oxides were synthesized by the reaction of 9-alkylfluoren-9-yllithium with the optically active epichlorohydrin at −70 °C and polymerized using KOH as an initiator. The molecular weight of the poly(3-(9-alkylfluoren-9-yl)propene oxide)s is larger than that of poly(4,4,4-triphenyl-1-butene oxide), which had been proved to take stable helical conformation in solution, and their molecular weight distributions were narrower (Mw/Mn = 1.02 to 1.09) than poly(4,4,4-triphenyl-1-butene oxide). By investigating of chiroptical properties of a series of polymers derived from optically active epoxide, it is suggested that the poly(3-(9-alkylfluoren-9-yl)propene oxide)s keep one-handed helical conformation in solution.

Optically active polyethers from chiral terminal epoxides with bulky group

Co-reporter:Jing Cao;Nian-Fa Yang;Pang-Deng Wang ;Li-Wen Yang

Polymer International 2008 Volume 57( Issue 3) pp:530-537

Publication Date(Web):

DOI:10.1002/pi.2380

Abstract

BACKGROUND: Although the backbone of polyethers from epoxides is flexible and less rigid in solution, we try to determine whether chiral terminal epoxides could form single-handed helical coiling in solution with the introduction of a bulky group at the 3-carbon that may fix the helix sense through the large interaction between pendants.

RESULTS: Several chiral terminal epoxides with bulky groups at the 3-carbon such as (S)-4,4,4-triphenyl-1-butene oxide ((S)-TPBO), (S)-4,4-diphenyl-1-butene oxide, (S)-4-benzyl-4,4-diphenyl-1-butene oxide and (S)-4,4-diphenyl-1-nonene oxide were synthesized and polymerized. Except for poly[(S)-TPBO], the polyepoxides could not retain a stable helical conformation in solution.

CONCLUSION: The conformation and length of polymers were directly related to the bulky substituent on the 3-carbon of chiral epoxides, and if the bulkiness and rigidity of the substituent were appropriate, the helical conformation of the polyethers formed could be retained in solution. Optically active polyethers would be potential substitutes for optically active poly(triphenylmethyl methacrylate) due to their much greater hydrolytic resistance. Copyright © 2007 Society of Chemical Industry

Helical Polymers from Optically Active Epoxides with Bulky Pendants

Co-reporter:Jing Cao;Nian-Fa Yang;Ji-Chao Li;Li-Wen Yang

Polymer Bulletin 2007 Volume 59( Issue 4) pp:481-490

Publication Date(Web):2007 November

DOI:10.1007/s00289-007-0788-3

The backbone of polyethers are often flexible because of inherent characteristics of ether linkage, but polyethers from chiral epoxides could form stable one-handed helical structure in solution state, if the pendants on the chain of polyethers are enough bulky and the distance between pendants and main chain is appropriate.

Well-controlled reversible addition–fragmentation chain transfer radical polymerisation under ultraviolet radiation at ambient temperature

Co-reporter:Lican Lu, Nianfa Yang and Yuanli Cai

Chemical Communications 2005 (Issue 42) pp:5287-5288

Publication Date(Web):10 Oct 2005

DOI:10.1039/B512057H

Controlled reversible addition–fragmentation chain transfer radical polymerisation of methyl acrylate was carried out under long-wave (λ ≥ 365 nm) ultraviolet radiation using an acylphosphine oxide as a photoinitiator at ambient temperature; the polymerisation shows a “living” character at high conversions of polymerisation and leads to well-defined polymers with narrow polydispersities (Mw/Mn < 1.1).

Phase selectively soluble dendritic derivative of 4-(N,N-dimethylamino)pyridine: an easily recyclable catalyst for Baylis–Hillman reactions

Co-reporter:Nian-Fa Yang, Hang Gong, Wei-Jun Tang, Qing-Hua Fan, Chang-Qun Cai, Li-Wen Yang

Journal of Molecular Catalysis A: Chemical 2005 Volume 233(1–2) pp:55-59

Publication Date(Web):24 May 2005

DOI:10.1016/j.molcata.2005.01.041

The Baylis–Hillman reaction of various aryl aldehydes with methyl vinyl ketone and acrylonitrile in the thermomorphic binary system (DMF/cyclohexane, 1/1, v/v) has been investigated. The phase selectively soluble alkyl-modified dendritic DMAP catalyst could be easily recycled via phase separation which was induced by cooling the temperature from 60 °C to room temperature. The corresponding Baylis–Hillman adducts were obtained in good yields and the recycled and reactivated dendritic catalyst almost gave the same results.A new type of soluble, alkyl-modified dendritic DMAP was synthesized, and successfully applied in the thermomorphic binary system (DMF/cyclohexane, 1/1, v/v) for Baylis–Hillman reaction, and the dendritic catalyst could be easily recycled by changing the temperature of the system.