STEREOGENIC LITHIUM CENTERS IN A COMPLEX BETWEEN N-BUTYLLITHIUM AND A DILITHIATED CHIRAL AMINE - SOLUTION STUDIES BY LI-6,H-1-HOESY, LI-6,LI-6-COSY, AND LI-6,LI-6-EXSY NMR
STEREOGENIC LITHIUM CENTERS IN A COMPLEX BETWEEN N-BUTYLLITHIUM AND A DILITHIATED CHIRAL AMINE - SOLUTION STUDIES BY LI-6,H-1-HOESY, LI-6,LI-6-COSY, AND LI-6,LI-6-EXSY NMR
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DOI：
10.1021/om00002a043
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发表时间：
1995-02-01
期刊：
影响因子：
2.8
通讯作者：
DAVIDSSON, O
中科院分区：
文献类型：
--
作者：
HILMERSSON, G;DAVIDSSON, O
的反应（2-甲氧基-（R）-1-苯乙基）（（S）-1-苯乙基）胺（1），其已用于不对称合成，在20 ℃下，在二乙基-d（10）醚（DEE）中与大量过量的[Li-6]-正丁基锂反应，导致在[Li-6]锂与[Li-6]-正丁基锂之间形成混合络合物，（2-甲氧基-（R）-1-苯基乙基）（2-（[Li-6]-锂硫基）-（S）-1-苯基乙基）酰胺（2）和两种[Li-6]-正丁基锂。该复合物在不对称环境中含有四个锂，这在H-1 NMR光谱中通过来自两个复合的正丁基锂的不等价α-质子的四个信号的出现而观察到。根据H-1，H-1-NOESY，H-1，Li-6-HOESY，Li-6，Li-6-COSY和Li-6，Li-6-EXSY光谱，推测该混合配合物的溶液结构为具有畸变立方核的四聚体。
The reaction of (2-methoxy-(R)-1-phenylethyl)((S)-1-phenylethyl)amine (1), which has been used in asymmetric synthesis, with [Li-6]-n-butyllithium in large excess in diethyl-d(10) ether (DEE) at 20 degrees C results in the formation of a mixed complex between [Li-6]lithium (2-methoxy-(R)-1-phenylethyl)(2-([Li-6]-lithio)-(S)-1-phenylethyl)amide (2) and two [Li-6]-n-butyllithiums. The complex contains four Lithiums in an asymmetric environment, which is observed in the H-1 NMR spectrum by the appearance of four signals from the nonequivalent alpha-protons of the two complexed n-butyllithiums. The solution structure of this mixed complex is proposed to be a tetramer with a distorted cubanoid core, on the basis of H-1,H-1-NOESY, H-1,Li-6-HOESY, Li-6,Li-6-COSY, and Li-6,Li-6-EXSY spectroscopy.