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【期刊论文】Distinct chemoselectivity in the reaction of N-(thio)phosphoryl imines with diethylzinc
周正洪, Xinpeng Ma, Xinyuan Xu, Chungui Wang, Guofeng Zhao, Zhenghong Zhou, Chuchi Tang
Journal of Organometallic Chemistry 692 (2007) 3685-3690,-0001,():
-1年11月30日
This report describes the reaction of N-(thio)phosphoryl imines with diethylzinc under different conditions. An interesting and distinct chemoselectivity between hydrogen-addition and ethyl-addition to imine double bond is disclosed: in weakly polar solvent, e.g. toluene, N-(thio)phosphoryl imines were exclusively reduced in excellent yields via a β-H transfer from diethylzinc to imine double bond; in polar solvents like THF, the reduction product was competitively formed as a major product together with the minor product resulting from ethyl-addition to imine double bond; in sharp contrast, in the presence of strong coordinative additive N,N,N0,N0-tetramethylethylenediamine (TMEDA), the ethylation product was formed exclusively from the reaction of N-(thio)phosphoryl imine with diethylzinc. These results are discussed and explained in terms of the coordination interactions between the imine, solvent, and additive with diethylzinc.
(, Thio), phosphorylimine, (, Thio), phosphinoylimine, Phosphonylimine, Diethylzinc, Reduction, Alkylation
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周正洪, Zhuohong Yang, Zhenghong Zhou, Ke He, Lixin Wang, Guofeng Zhao, Qilin Zhou and Chuchi Tang
Tetrahedron: Asymmetry 14 (2003) 3937-3941,-0001,():
-1年11月30日
Some new chiral cyclic o-hydroxylarylphosphonodiamides were synthesized from (−)-α-phenylethylamine and found to be efficient ligands for the Ti(OPr-i )4 catalyzed asymmetric trimethylsilylcyanation of aromatic aldehydes. Corresponding cyanohydrins were obtained in good chemical yield and enantiomeric excesses up to 90%.
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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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周正洪, Hongying Tang, Peng Gao, Guofeng Zhao, Zhenghong Zhou, Liangnian He, Chuchi Tang
Catalysis Communications 8 (2007) 1811-1814,-0001,():
-1年11月30日
(1R,2R)-(—)-2-Dimethylamino-1-(4-nitrophenyl)-1,3-propanediol (2) was prepared starting from the readily available precursor of antibiotics chloramphenicol. The combination of compound 2 and L-proline have been found to be an efficient cocatalyst for the asymmetric Morita-Baylis-Hillman (MBH) reaction between methyl vinyl ketone (MVK) and aromatic aldehydes. The corresponding adducts were formed in reasonable chemical yields with good enantioselectivities (up to 82% ee). Performance of parallel cocatalytic reactions with chiral amine 2 and the two enantiomers of proline revealed that it is the proline stereochemistry that determines the configuration of the newly formed chiral center.
(, 1R,, 2R), -(, —), -2-Dimethylamino-1-(, 4-nitrophenyl), -1,, 3-propanediol, Cocatalyst, Asymmetric Morita-Baylis-Hillman reaction, Enantioselectivity
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周正洪, Zhou Zhenghong, Tang Yilong, Wang Lixin, Zhao Guofeng, Zhou Qilin, Tang Chuchi
SYNTHESIS 2004, No. 2, pp. 0217-0220,-0001,():
-1年11月30日
α-Disubstituted pyrrolidine-2-methanols were synthesized starting from L-proline and their application as chiral auxiliary in the asymmetric NaBH4 reduction of α,β-unsaturated triazolyl ketones was investigated. The corresponding α,β-unsaturated triazolyl alcohol derivatives (Uniconazole and Diniconazole) were obtained in good chemical yields with high ee values (up to 93%).
triazoles, L-proline, asymmetric reduction
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