Chiral Aminoalcohols and Squaric Acid Amides as Ligands for Asymmetric Borane Reduction of Ketones: Insight to In Situ Formed Catalytic System by DOSY and Multinuclear NMR Experiments
作者:Yana Nikolova、Georgi M. Dobrikov、Zhanina Petkova、Pavletta Shestakova
DOI:10.3390/molecules26226865
日期:——
insight on the in situ formation and stability at room temperature of intermediates generated from ligands and borane as possible precursors of the oxazaborolidine-based catalytic system has been obtained by 1H DOSY and multinuclear 1D and 2D (1H, 10/11B, 13C, 15N) NMR spectroscopy of equimolar mixtures of borane and selected ligands. These results contribute to better understanding the complexity of the
在用 BH 3 ·SMe 2还原 α-氯苯乙酮的模型反应中,对一系列方酸酰胺(以 66-99% 的分离产率合成)和一组手性氨基醇作为配体进行了比较研究。在所有情况下,氨基醇都表现出更好的效率(高达 94% ee ),而相应的方酰胺仅实现了较差的不对称诱导。通过1 H DOSY 和多核 1D 和 2D ( 1 H, 10/11 B , 13 C, 15 N) 硼烷和选定配体的等摩尔混合物的NMR谱。这些结果有助于更好地理解在可能形成恶唑硼烷之前反应混合物中发生的过程的复杂性,这对于 α-氯苯乙酮硼烷还原中实现的对映选择性程度起着至关重要的作用。