Chiral organometallic reagents, XII. On the racemization of α??hetero??substituted benzyllithium compounds

H Ahlbrecht, J Harbach, RW Hoffmann…

文献索引：Ahlbrecht, Hubertus; Harbach, Juergen; Hoffmann, Reinhard W.; Ruhland, Thomas Liebigs Annalen, 1995 , # 2 p. 211 - 216

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被引用次数: 25

摘要

Abstract Benzyllithium compounds carrying a benzylthio substituent (6), a benzylseleno substituent (8), and an isopropyl (methyl) amino substituent (14) have been generated. Racemization barriers have been determined in THF by monitoring the coalescence of signals of diastereotopic groups in the 1 H-NMR spectra. The barrier for 6 amounts to a ΔH≠ of 7.5 kcal mol− 1 and ΔS≠ of− 12 cal mol− 1 K− 1 corresponding to a ΔG math ...