New chiral tetraaza ligands for the efficient enantioselective addition of dialkylzinc to aromatic aldehydes
作者:M. Isabel Burguete、Jorge Escorihuela、Santiago V. Luis、Agustí Lledós、Gregori Ujaque
DOI:10.1016/j.tet.2008.07.099
日期:2008.10
enantioselective addition of dialkylzinc to aldehydes. These bis(amino amide) ligands show high enantioselectivity in the addition of organozincs to aromatic aldehydes. Different structural elements on the ligands seem to play an important role in determining the observed enantioselectivity. Ligand 4b (N,N′-bis(N-l-valinyl)-1,3-diaminopropane, with an aliphatic spacer with 3C atoms) catalyzed the addition of Et2Zn
研究了一系列手性四氮杂配体,用于将二烷基锌对映体选择性加成到醛中。这些双(氨基酰胺)配体在将有机锌添加到芳族醛中时显示出高对映选择性。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。配体4b(N,N'-双(N -1-戊基)-1,3-二氨基丙烷,带有带有3C原子的脂族间隔基)催化Et 2的添加锌转化为苯甲醛,1-萘醛,4-甲氧基苯甲醛和4-氯苯甲醛,得到相应的醇产物,其转化率和选择性极好,对映选择性分别为99%,97%,98%和82%。DFT计算提供了对映过程的机理的理解。