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周正洪, Zebing Zeng, Guofeng Zhao, Peng Gao, Hongying Tang, Bo Chen, Zhenghong Zhou, Chuchi Tang
Catalysis Communications 8 (2007) 1443-1446,-0001,():
-1年11月30日
A novel chiral salen ligand (R,R)-2 was synthesized through the condensation of (R,R)-11,12-diamino-9,10-dihydro-9,10-ethanoanthracene and 3,5-di-tert-butylsalicylaldehyde. The (salen)Ti(IV) complex formed in situ upon the treatment of ligand 2 and Ti(OPr-i)4 was proved to be an efficient catalyst for the asymmetric trimethylsilylcyanation of aldehydes. The corresponding cyanohydrins were obtained in high yields (75-97%) with moderate to good enantioselectivities (48-76%).
Chiral (, salen), Ti(, IV), complex, Asymmetric silylcyanation, Enantioselectivity, Aldehydes
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周正洪, Hongying Tang, Guofeng Zhao, Zhenghong Zhou, Qilin Zhou and Chuchi Tang
Tetrahedron Letters 47 (2006) 5717-5721,-0001,():
-1年11月30日
A chiral benzodiazepine derivative 1 was synthesized starting from o-nitrobenzoyl chloride and methyl L-prolinate hydrochloride. Diastereomeric (1R,2R,1’S)-(+)-2-[N-methyl-N-(α-phenylethyl)amino]cyclohexanol 3a and (1S,2S,1’S)-(+)-2-[N-methyl-N-(α-phenylethyl)amino]cyclohexanol 3b were synthesized starting from (S)-α-phenylethylamine and cyclohexene oxide via ringopening, diastereomer separation and N-methylation. (S,S)-octahydrodipyrrolo[1,2-a:1’,2’-d]pyrazin 5 was synthesized from methyl L-prolinate. Chiral tertiary amines 1, 3a, 3b and 5 almost cannot catalyze the Baylis–Hillman reaction between o-nitrobenzaldehyde and methyl vinyl ketone (MVK). However, they functioned as efficient catalysts for this reaction in the presence of L-proline. The corresponding adducts were obtained in good yields with enantioselectivity of 83% ee, 81% ee, 51% ee and 66% ee, respectively.
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周正洪, Zhenghong Zhou, Zhaoming Li, Wang Quanyong, Bing Liu, Kangying Li, Guofeng Zhao, Qilin Zhou, Chuchi Tang
Journal of Organometallic Chemistry 691 (2006) 5790-5797,-0001,():
-1年11月30日
A series of chiral bis-Schiff bases were synthesized starting from (1R,2R)-(+)-diaminocyclohexane, (+)-cis-1,2,2-trimethyl-1,3-diaminocyclopentane, (R)-2,2’-diamino-1,1’-binaphthalene, and (1S,2S)-diphenyl-1,2-ethanediamine. The enantioselective ring-opening of meso epoxides with dithiophosphorus acids catalyzed by a (salen)Ti(IV) complex formed in situ upon the treatment of Ti(OPr-i)4 and the aforementioned chiral Schiff base was realized. The resulting products were obtained with low to good enantioselectivities (up to 73% ee). The (salen)Ti(IV) complex containing the backbone of 1,2-diaminocyclohexane exhibited the best enantioselectivity. The substituents in dithiophosphorus acids and those on the salen aromatic ring have a significant influence on the reaction. Moderate enantioselectivity were obtained for the (salen)Ti(IV) complex catalyzed ring-opening of racemic monosubstituted epoxides. High regioselectivity was observed for the alkyl substituted epoxides, whereas poor regioselectivity was obtained for the aryl substituted ones.
(, Salen), Ti(, IV), complex, Asymmetric ring-opening, Epoxide, Dithiophosphorus acid
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周正洪, Ke He, Zhenghong Zhou, Lixin Wang, Kangying Li, Guofeng Zhao, Qilin Zhou and Chuchi Tang
Tetrahedron 60 (2004) 10505-10513,-0001,():
-1年11月30日
Some new chiral bifunctional o-hydroxyarylphosphonodiamides were synthesized starting from (+)-cis-1,2,2-trimethylcyclopentane-1,3-diamine and the absolute configuration of the phosphorus atom was determined by X-ray diffraction analysis. Excellent enantioselectivity (up to 98% ee) was achieved in asymmetric silylcyanation of aromatic aldehydes using a chiral titanium complex formed in situ from Ti(OiPr)4 and o-hydroxyarylphosphonodiamide as the catalyst.
Chiral cyclophosphonodiamide, Asymmetric silylcyanation, Catalysis, Enantioselectivity, Aromatic aldehyde
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周正洪, Xinyuan Xu, Chungui Wang, Zhenghong Zhou, Xiaofang Tang, Zhengjie He, and Chuchi Tang
Eur. J. Org. Chem. 2007, 4487-4491,-0001,():
-1年11月30日
In the presence of an effective air-stable nucleophilic trialkylphosphane orgaocatalyst, 1,3,5-triaza-7-phosphaadamantane, N-diethoxythiophosphorylimines 1 and N-diphenylthiophosphinoylimines 2 exhibited good reactivity in the methyl vinyl ketone or methyl acrylate based aza-Morita–Baylis–Hillman reaction. The corresponding products were obtained in fair-to-excellent chemical yields. Moreover, the chiral-imine-induced diastereoselective aza-MBH reaction was also realized with 90% de. This reaction provides a convenient method for the synthesis of synthetically valuable α-methylene-β-amino ketone or acid derivatives.
Imines, Alkenes, Aza-Morita–Baylis–Hillman reaction, Ketones
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