Evans Enolates: Solution Structures of Lithiated Oxazolidinone-Derived Enolates

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• 作者：Evan H. Tallmadge ; David B. Collum
• 刊名：Journal of the American Chemical Society
• 出版年：2015
• 出版时间：October 14, 2015
• 年：2015
• 卷：137
• 期：40
• 页码：13087-13095
• 全文大小：646K
• ISSN：1520-5126

文摘

The results of a combination of ⁶Li and ¹³C NMR spectroscopic and computational studies of oxazolidinone-based lithium enolates鈥擡vans enolates鈥攊n tetrahydrofuran (THF) solution revealed a mixture of dimers, tetramers, and oligomers (possibly ladders). The distribution depended on the structure of the oxazolidinone auxiliary, substituent on the enolate, and THF concentration (in THF/toluene mixtures). The unsolvated tetrameric form contained a Db>2db>-symmetric core structure, whereas the dimers were determined experimentally and computationally to be trisolvates with several isomeric forms.