Structures of β-Amino Ester Enolates: New Strategies Using the Method of Continuous Variation

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• 作者：Lara R. Liou ; Anne J. McNeil ; Gilman E. S. Toombes ; David B. Collum
• 刊名：Journal of the American Chemical Society
• 出版年：2008
• 出版时间：December 24, 2008
• 年：2008
• 卷：130
• 期：51
• 页码：17334-17341
• 全文大小：410K
• 年卷期：v.130,no.51(December 24, 2008)
• ISSN：1520-5126

文摘

The solution structures of four enolates derived from β-amino esters are investigated using ⁶Li NMR spectroscopy in conjunction with the method of continuous variation (method of Job). Ensembles of homo- and heteroaggregated enolates are generated by mixing enantiomers of a single enolate (R/S mixtures), opposite antipodes of two different enolates (R/S′ mixtures), and the same antipodes of two different enolates (R/R′ mixtures). The numbers of observable aggregates and their dependence on the mole fraction of the two enolates confirm the hexamer assignments. Inherent symmetries observable in the ⁶Li NMR spectra show the stereochemistry of chelation about the hexagonal drum.