Chiral bisphosphazides as dual basic enantioselective catalysts.
Chiral bisphosphazides as dual basic enantioselective catalysts.
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DOI：
10.1002/chem.200800230
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发表时间：
2008-06
期刊：
影响因子：
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通讯作者：
H. Naka;Nobuhiko Kanase;M. Ueno;Y. Kondo
中科院分区：
文献类型：
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作者：
H. Naka;Nobuhiko Kanase;M. Ueno;Y. Kondo
手性双磷酸盐与锂盐络合物能有效催化二烷基丙二酸酯与开环烯酮的1，4-直接不对称加成反应。双磷酰胺和锂盐化学计量比的光谱研究表明，活性对映选择性催化剂形成了1：1的物种。结果表明，催化剂生成了质子化磷氮化物与手性亲核剂的络合物作为关键中间体。磷酰肼部分似乎是一种很有前途的立体和化学选择性催化转化的双重基本功能。
Chiral bisphosphazides complexed with lithium salts efficiently catalyze the direct enantioselective 1,4-addition of dialkyl malonates to acyclic enones. Spectroscopic studies on the stoichiometry of the bisphosphazide and lithium salt have indicated the formation of a 1:1 species as the active enantioselective catalyst. It is suggested that the catalyst generates a complex of the protonated phosphazide and the chiral nucleophile as the key intermediate. The phosphazide moiety appears to be a promising dual basic functionality for stereo- and chemoselective catalytic transformations.