Chiral Lithium Diamides Derived from Linked N-Isopropyl Valinol or Alaninol

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• 作者：Chicheung Su ; Jie Guang ; Weibin Li ; Kuiwang Wu ; Russell Hopson ; Paul G. Williard
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：August 20, 2014
• 年：2014
• 卷：136
• 期：33
• 页码：11735-11747
• 全文大小：829K
• ISSN：1520-5126

文摘

Four different chiral diamino diethers synthesized from N-isopropyl valinol or N-isopropyl alaninol were lithiated with n-butyllithium in tetrahydrofuran or diethyl ether. Crystal structures of the dilithiated diamino diethers were determined by X-ray diffraction. Three dilithiated diamino diethers including (2S,2鈥?i>S)-1,1鈥?(butane-1,4-diylbis(oxy))bis(N-isopropylpropan-2-amine) 7, (2S,2鈥?i>S)-1,1鈥?(pentane-1,5-diylbis(oxy))bis(N-isopropylpropan-2-amine) 8, and (2S,2鈥?i>S)-1,1鈥?(heptane-1,7-diylbis(oxy))bis(N-isopropyl-3-methylbutan-2-amine) 9 are dimers, whereas dilithiated (2S,2鈥?i>S)-1,1鈥?(pentane-1,5-diylbis(oxy))bis(N-isopropyl-3-methylbutan-2-amine) 10 is a monomer. The lithium atoms in all crystal structures adopt a nonequivalent coordination protocol and exist in two different environments in which one of the lithium atoms is tetra-coordinated while the other one is tri-coordinated. The solution structures of the dilithiated diamino diethers are also characterized by a variety of NMR experiments including diffusion-ordered NMR spectroscopy (DOSY) with diffusion coefficient-formula (D-FW) weight correlation analyses and other one- and two-dimensional NMR techniques.