Co-reporter:Cheng Peng;Jiaojiao Zhai;Mingqiang Xue
Organic & Biomolecular Chemistry 2017 vol. 15(Issue 18) pp:3968-3974
Publication Date(Web):2017/05/10
DOI:10.1039/C7OB00640C
Lanthanide amide-catalyzed one-pot reaction of isatins, dialkyl phosphite, and activated alkenes was developed and a series of spiro[cyclopropan-1,3′-oxindoles] were obtained in moderate to excellent yields. The reaction is stereoselective and the two substituents at the 2 and 3-positions of the cyclopropane in the major product are in the trans configuration. A four-step mechanism involving the Pudovik reaction, Brook rearrangement, Michael addition, and intramolecular nucleophilic substitution is proposed, and an umpolung strategy was used in the process.
Co-reporter:Mingqiang Xue, Yu Zheng, Yubiao Hong, Yingming Yao, Fan Xu, Yong Zhang and Qi Shen
Dalton Transactions 2015 vol. 44(Issue 46) pp:20075-20086
Publication Date(Web):20 Oct 2015
DOI:10.1039/C5DT03674G
Reduction reactions of bis(β-diketiminate)lanthanide(III) chlorides formed in situ by reactions of anhydrous LnCl3 with 2 equiv. of sodium salt of the β-diketiminate ligand in THF with a Na/K alloy afforded a series of bis(β-diketiminate)lanthanide(II) complexes LnL2(THF)n (L = L2,6-Me2 = [N(2,6-Me2C6H3)C(Me)]2CH−, n = 1, Ln = Eu (1); L = L2,4,6-Me3 = [N(2,4,6-Me3C6H2)C(Me)]2CH−, n = 1, Ln = Eu (2); L = L2,6-iPr2 = [N(2,6-iPr2C6H3)C(Me)]2CH−, n = 0, Ln = Eu (3), Sm (4); L = L2,6-ipr2Ph = [(2,6-iPr2C6H3)NC(Me)CHC(Me)N(C6H5)]−, n = 0, Ln = Eu (5), Yb (6); L = L2-Me = [N(2-MeC6H4)C(Me)]2CH−, n = 1, Ln = Yb (7)) in high yields. All the complexes, especially the complexes of SmII (4) and EuII (5), were found to be excellent pre-catalysts for catalytic addition of amines to carbodiimides to multi-substituted guanidines with a wide scope of substrates. The activity depends both on the central metals and the ligands with the active sequence of YbII < EuII and EuII < SmII and L2,6-Me2 < L2,4,6-Me3 ∼ L2,6-iPr2 < L2,6-ipr2Ph for the ligands. The mechanistic study by the isolation of guanidinate species and their reactivity revealed that EuII monoguanidinate complexes Eu(L2,6-Me2)[(C6H5N)C(NHCy)(NCy)](DME) (8) and Eu(L2,6-ipr2Ph)[(C6H5N)C(NHCy)(NCy)](THF)2 (9) should be the key active intermediates for the systems with EuII complexes and a YbIII bis(guanidinate) complex Yb(L2-Me)[(C6H5N)C(NHCy)(NCy)]2 (11) for the system using a YbII complex.
Co-reporter:Lu Hua, Zhigang Yao, Fan Xu and Qi Shen
RSC Advances 2014 vol. 4(Issue 7) pp:3113-3120
Publication Date(Web):25 Nov 2013
DOI:10.1039/C3RA44829K
A catalyst-controlled chemoselective reaction of o-aminocinnamate and isothiocyanates in the presence of lanthanide complexes under mild and solvent-free conditions was developed. 2-Amino-3,1-benzothiazines were obtained in high yields when the reactions were catalyzed by Yb(OTf)3, whereas those catalyzed by [(Me3Si)2N]3La(μ-Cl)Li(THF)3 afforded 3,4-dihydroquinazoline-2-thiones in high to excellent yields. The mechanism for the product selectivity and high efficiency of the reaction was proposed.
Co-reporter:Guoyao Li, Lu Wang, Zhigang Yao, Fan Xu
Tetrahedron: Asymmetry 2014 Volume 25(13–14) pp:989-996
Publication Date(Web):31 July 2014
DOI:10.1016/j.tetasy.2014.06.008
Co-reporter:Aijiao Zhang;Lijian Cai;Zhigang Yao;Qi Shen
Heteroatom Chemistry 2013 Volume 24( Issue 5) pp:345-354
Publication Date(Web):
DOI:10.1002/hc.21099
ABSTRACT
Lanthanide-catalyzed addition of diethyl phosphite with chalcones was achieved under mild conditions. The reaction exhibited good product selectivity using different catalysts. γ-Oxophosphonates were obtained in high yields in the reactions catalyzed by Yb(OAr)3(THF)2, while those catalyzed by [(Me3Si)2N]3La(μ-Cl)Li(THF)3 afforded 1,2-oxaphospholane-5-phosphonates as the main products in moderate to good yields. This methodology provides facile and practical approaches to the corresponding organophosphorus compounds with biological interest.
Co-reporter:Jie Huang;Yong Yu;Lu Hua;ZhiGang Yao;Qi Shen
Science Bulletin 2013 Volume 58( Issue 7) pp:717-723
Publication Date(Web):2013 March
DOI:10.1007/s11434-012-5631-z
A clean, efficient method to synthesize 2-amino-4H-3,1-benzothiazines by ytterbium chloride-catalyzed tandem addition-cyclization reaction of o-aminocinnamate and isothiocyanates under solvent-free conditions is developed.
Co-reporter:Lu Wang;Zhigang Yao;Qi Shen
Heteroatom Chemistry 2012 Volume 23( Issue 5) pp:449-456
Publication Date(Web):
DOI:10.1002/hc.21036
Abstract
The tetracoordinated lanthanide amides [(Me3Si)2N]3Ln(µ-Cl)Li(THF)3 were found to serve as highly active catalysts for the phospho-Aldol-Brook rearrangement reaction of various dialkyl phosphites and isatins. The reactions produced dialkyl 2-oxoindolin-3-yl phosphates in good to excellent yields in the presence of 1 mol% [(Me3Si)2N]3La(µ-Cl)Li(THF)3 at room temperature within 5 min. A mechanism for this highly efficient process was proposed. © 2012 Wiley Periodicals, Inc. Heteroatom Chem 23:449–456, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.21036
Co-reporter:QianNan Wang;ZhiGang Yao;Qi Shen
Science Bulletin 2012 Volume 57( Issue 14) pp:1612-1615
Publication Date(Web):2012 May
DOI:10.1007/s11434-011-4744-0
An efficient method was developed for the synthesis of arylidene heterobicyclic 3-cyano-2-pyridones via ytterbium chloride catalyzed tandem condensation of aromatic aldehydes, cyclic ketones, and cyanoacetamide. The conditions and scope of the reaction were investigated and a reaction mechanism was proposed.
Co-reporter:XueHua Zhu;Qi Shen
Science Bulletin 2012 Volume 57( Issue 26) pp:3419-3422
Publication Date(Web):2012 September
DOI:10.1007/s11434-012-5332-7
A catalytic addition of amine N-H bonds to carbodiimides using aluminum chloride as a Lewis acid catalyst is developed. The reaction proceeds under mild conditions without solvent to afford a series of substituted guanidines in good to excellent yields using a wide range of amines as substrates. Evidence of the proposed mechanism is provided by in situ infrared spectroscopy.
Co-reporter:Lijian Cai;Xiaofeng Ji;Zhigang Yao;Qi Shen
Chinese Journal of Chemistry 2011 Volume 29( Issue 9) pp:1880-1886
Publication Date(Web):
DOI:10.1002/cjoc.201180328
Abstract
An efficient method is developed for the synthesis of functionalized benzimidazoles and perimidines by the condensation of aryl diamines with β-carbonyl compounds catalyzed by ytterbium chloride. The reactions give good yields under mild conditions. A mechanism involving a lanthanide activated CC bond cleavage is proposed.
Co-reporter:HaiDong Liu;Lan Li;HongTing Sheng;XueHua Zhu
Science Bulletin 2011 Volume 56( Issue 13) pp:1357-1360
Publication Date(Web):2011 May
DOI:10.1007/s11434-011-4451-x
Catalytic acylation of nitriles with esters in the presence of 10 mol% NdNa8(OtBu)10(OH) is developed. The procedure is suitable for both enolizable and nonenolizable esters and affords β-ketonitriles in moderate to high yields. The heterometallic alkoxide cluster NdNa8(OtBu)10(OH) is structurally characterized by X-ray diffraction, and a mechanism for the production of β-ketonitriles using the cluster is proposed and verified.
Co-reporter:Yong Yu;Jun Zhou;Zhigang Yao;Qi Shen
Heteroatom Chemistry 2010 Volume 21( Issue 5) pp:351-354
Publication Date(Web):
DOI:10.1002/hc.20612
Abstract
A simple and efficient method for the cis-selective synthesis of pyrano- and furano[3,2-c]quinolines via gadolinium chloride catalyzed one-pot aza–Diels–Alder reaction is described. Solvent conditions played a major role in affecting the diastereoselectivity of the products. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:351–354, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20612
Co-reporter:Qingmao Wu, Jun Zhou, Zhigang Yao, Fan Xu, and Qi Shen
The Journal of Organic Chemistry 2010 Volume 75(Issue 21) pp:7498-7501
Publication Date(Web):October 6, 2010
DOI:10.1021/jo101743e
A highly efficient method for the synthesis of α-hydroxy phosphonates via lanthanide amides [(Me3Si)2N]3Ln(μ-Cl)Li(THF)3 catalyzed hydrophosphonylation of aromatic aldehydes was developed. The reactions produced the products in excellent yields in the presence of 0.1 mol % [(Me3Si)2N]3La(μ-Cl)Li(THF)3 at room temperature within 5 min. The existence of LiCl in the catalyst was a key factor affecting the catalytic activity. The mechanism for the process of high efficiency was proposed.
Co-reporter:ChengYi Cai;Lan Li;Qi Shen
Science Bulletin 2010 Volume 55( Issue 32) pp:3641-3643
Publication Date(Web):2010 November
DOI:10.1007/s11434-010-4139-7
Heterobimetallic clusters of Na8Ln(OtBu)10(OH) (Ln = ytterbium, europium, samarium and neodymium) are found to be useful catalysts for amidation of aldehydes with amines under mild conditions. The catalytic activity depends on the central metal ion in the cluster, and the order activity is ytterbium < europium < samarium ≈ neodymium. The catalysts show a wide range of scope in their activity towards amines including aliphatic amines and secondary cyclic amines such as pyrrolidine and piperidine.
Co-reporter:LianBin Yao;Qi Shen
Science Bulletin 2010 Volume 55( Issue 36) pp:4108-4111
Publication Date(Web):2010 December
DOI:10.1007/s11434-010-4230-0
An efficient method for the synthesis of tetrahydroquinoline derivatives via lanthanide halides catalyzed domino reactions of arylamines with dihydropyran is described. Either the cis or the trans isomer can be obtained as the major product in good yield by changing the catalyst and reaction conditions.
Co-reporter:Lan LI;Hongting SHENG;Qi SHEN
Chinese Journal of Chemistry 2009 Volume 27( Issue 6) pp:1127-1131
Publication Date(Web):
DOI:10.1002/cjoc.200990188
Abstract
The heterometal alkoxide clusters of Group 3 metal and lanthanides with sodium Ln2Na8(OCH2CH2NMe2)12(OH)2 (Ln=Y, lanthanide) were found to serve as highly active catalysts for the Tishchenko reaction of various aldehydes to form the corresponding esters. The reaction scope and the influence of lanthanide and sodium metal on the catalytic activity were investigated, and the proposed mechanism of the reaction was discussed.
Co-reporter:Huihui Zhang, Zhuqing Zhou, Zhigang Yao, Fan Xu, Qi Shen
Tetrahedron Letters 2009 50(14) pp: 1622-1624
Publication Date(Web):
DOI:10.1016/j.tetlet.2009.01.103
Co-reporter:Shan-E FENG;Qi SHEN
Chinese Journal of Chemistry 2008 Volume 26( Issue 7) pp:1163-1167
Publication Date(Web):
DOI:10.1002/cjoc.200890213
Abstract
The condensation of o-phenylenediamine with various α,β-unsaturated ketones was efficiently catalyzed by lanthanide trichloride and a variety of 1,5-benzodiazepines were synthesized in moderate to high yields under mild conditions. The reactions catalyzed by ytterbium trichloride were investigated emphatically.
Co-reporter:Zhuqing Zhou;Xiaoyan Han;Jun Zhou;Qi Shen
European Journal of Organic Chemistry 2007 Volume 2007(Issue 31) pp:5265-5269
Publication Date(Web):30 AUG 2007
DOI:10.1002/ejoc.200700288
Three-component aza-Diels–Alder reactions involving aromatic aldehydes, aromatic amines, and dihydropyran or dihydrofuran are effectively catalyzed by samarium diiodide to afford pyrano[3,2-c]- or furano[3,2-c]quinolines in good yields and with high stereoselectivities. Either the cis or the trans isomers can be obtained as the major products by conveniently controlling reaction conditions.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Co-reporter:Xuehua Zhu, Guoyao Li, Fan Xu, Yong Zhang, Mingqiang Xue, Qi Shen
Tetrahedron (16 March 2017) Volume 73(Issue 11) pp:
Publication Date(Web):16 March 2017
DOI:10.1016/j.tet.2017.01.051
Cationic lanthanide complexes of the type [Ln(CH3CN)9]3+[(AlCl4)3]3–·CH3CN (Ln = Pr, Nd, Sm, Gd, Er, Yb, Y) served as effective catalysts for the intramolecular hydroalkoxylation/cyclization of unactivated alkenols to yield the cyclic ethers with Markovnikov regioselectivity under mild conditions. Novel cationic complexes, [AlCl(CH3CN)5]2+[(AlCl4)2]2–·CH3CN and [Nd(CH3CN)9]3+[(FeCl4)3]3–·CH3CN, were synthesized and evaluated for the intramolecular hydroalkoxylation/cyclization of unactivated alkenols for comparison. The active sequence of [Nd(CH3CN)9]3+[(FeCl4)3]3–·CH3CN < [AlCl(CH3CN)5]2+[(AlCl4)2]2–·CH3CN < [Nd(CH3CN)9]3+[(AlCl4)3]3–·CH3CN observed indicated that both the cation and anion have great influence on the activity. Comparative study on the activity of AlCl3 and its cationic complex [AlCl(CH3CN)5]2+[(AlCl4)2]2–·CH3CN revealed the formation of the cationic Al center enhanced the activity greatly. The 1H NMR studies indicated the activation of hydroxyl and olefin by the cationic Ln3+ center were involved in the reaction pathways.
Co-reporter:Cheng Peng, Jiaojiao Zhai, Mingqiang Xue and Fan Xu
Organic & Biomolecular Chemistry 2017 - vol. 15(Issue 18) pp:NaN3974-3974
Publication Date(Web):2017/04/18
DOI:10.1039/C7OB00640C
Lanthanide amide-catalyzed one-pot reaction of isatins, dialkyl phosphite, and activated alkenes was developed and a series of spiro[cyclopropan-1,3′-oxindoles] were obtained in moderate to excellent yields. The reaction is stereoselective and the two substituents at the 2 and 3-positions of the cyclopropane in the major product are in the trans configuration. A four-step mechanism involving the Pudovik reaction, Brook rearrangement, Michael addition, and intramolecular nucleophilic substitution is proposed, and an umpolung strategy was used in the process.
Co-reporter:Mingqiang Xue, Yu Zheng, Yubiao Hong, Yingming Yao, Fan Xu, Yong Zhang and Qi Shen
Dalton Transactions 2015 - vol. 44(Issue 46) pp:NaN20086-20086
Publication Date(Web):2015/10/20
DOI:10.1039/C5DT03674G
Reduction reactions of bis(β-diketiminate)lanthanide(III) chlorides formed in situ by reactions of anhydrous LnCl3 with 2 equiv. of sodium salt of the β-diketiminate ligand in THF with a Na/K alloy afforded a series of bis(β-diketiminate)lanthanide(II) complexes LnL2(THF)n (L = L2,6-Me2 = [N(2,6-Me2C6H3)C(Me)]2CH−, n = 1, Ln = Eu (1); L = L2,4,6-Me3 = [N(2,4,6-Me3C6H2)C(Me)]2CH−, n = 1, Ln = Eu (2); L = L2,6-iPr2 = [N(2,6-iPr2C6H3)C(Me)]2CH−, n = 0, Ln = Eu (3), Sm (4); L = L2,6-ipr2Ph = [(2,6-iPr2C6H3)NC(Me)CHC(Me)N(C6H5)]−, n = 0, Ln = Eu (5), Yb (6); L = L2-Me = [N(2-MeC6H4)C(Me)]2CH−, n = 1, Ln = Yb (7)) in high yields. All the complexes, especially the complexes of SmII (4) and EuII (5), were found to be excellent pre-catalysts for catalytic addition of amines to carbodiimides to multi-substituted guanidines with a wide scope of substrates. The activity depends both on the central metals and the ligands with the active sequence of YbII < EuII and EuII < SmII and L2,6-Me2 < L2,4,6-Me3 ∼ L2,6-iPr2 < L2,6-ipr2Ph for the ligands. The mechanistic study by the isolation of guanidinate species and their reactivity revealed that EuII monoguanidinate complexes Eu(L2,6-Me2)[(C6H5N)C(NHCy)(NCy)](DME) (8) and Eu(L2,6-ipr2Ph)[(C6H5N)C(NHCy)(NCy)](THF)2 (9) should be the key active intermediates for the systems with EuII complexes and a YbIII bis(guanidinate) complex Yb(L2-Me)[(C6H5N)C(NHCy)(NCy)]2 (11) for the system using a YbII complex.
![[4-(2-HYDROXY-2-METHYLPROPYL)PHENYL]ACETIC ACID](/data/chemimg/99000/572-59-8.png)
![[4-(2-HYDROXY-2-METHYLPROPYL)PHENYL]ACETIC ACID](/data/chemimg/99000/572-59-8_b.png)