Highly exo-selective and enantioselective cycloaddition reactions of nitrones catalyzed by a chiral binaphthyldiimine-Ni(II) complex.
Highly exo-selective and enantioselective cycloaddition reactions of nitrones catalyzed by a chiral binaphthyldiimine-Ni(II) complex.
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DOI：
10.1021/ol050397h
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发表时间：
2005-03
期刊：
影响因子：
5.2
通讯作者：
H. Suga;T. Nakajima;K. Itoh;A. Kakehi,
中科院分区：
文献类型：
--
作者：
H. Suga;T. Nakajima;K. Itoh;A. Kakehi,
[反应：见正文]显著水平的外向选择性(exo：endo=>；在4A分子筛存在下，N，N‘-bis(3，5-dichrolo-2-hydroxybenzylidene)-1，1’-binaphthyl-2，2‘-diamine和Ni(ClO4)2×6H2O在四氯甲烷中容易合成的手性联二亚胺-镍(II)络合物(5-20摩尔%)催化硝酮与3-(2-烷基)-2-噻唑硫酮的1，3-偶极环加成反应，获得了99：1~86：14)和对映体选择性(95~82%ee)。
[reaction: see text] Significant levels of exo-selectivity (exo:endo = >99:1 to 86:14) and enantioselectivity (95-82% ee) were obtained in the 1,3-dipolar cycloadditions of a number of nitrones with 3-(2-alkenoyl)-2-thiazolidinethiones, using the chiral binaphthyldiimine-Ni(II) complex (5-20 mol %), which was easily prepared form N,N'-bis(3,5-dichrolo-2-hydroxybenzylidene)-1,1'-binaphthyl-2,2'-diamine and Ni(ClO4)2 x 6H2O in CHCl3 in the presence of 4 A molecular sieves, as a chiral Lewis acid catalyst.