C2 symmetrical nickel complexes derived from α-amino amides as efficient catalysts for the enantioselective addition of dialkylzinc reagents to aldehydes
作者:Jorge Escorihuela、Belen Altava、M. Isabel Burguete、Santiago V. Luis
DOI:10.1016/j.tet.2012.11.025
日期:2013.1
amides were studied for the enantioselective addition of dialkylzinc reagents to aldehydes. Different structural elements on the ligands seem to play an important role in determining the observed enantioselectivity. Through optimization of structure and reaction conditions, the best ligand provided secondary alcohols in excellent yields (up to 98%) and enantioselectivity of up to 99% ee for (R)-enantiomer
研究了由α-氨基酰胺衍生的一系列C 2对称的1:2 Ni:L络合物,用于将二烷基锌试剂对映异构地加成到醛中。配体上的不同结构元素似乎在确定观察到的对映选择性中起重要作用。通过的结构和反应条件的优化,最佳配位体以优良产率(高达98%)和高达99%ee的对(对映选择性的提供仲醇ř)-对映体。已经提出了一种过渡状态模型,用于基于DFT级别的计算结果解释所观察到的对映选择性。非常有趣的是,计算表明通过羰基氧的孤对与氨基氢原子的缔合,醛与金属络合物的配位模型。