Catalytic asymmetric phase-transfer reactions using tartrate-derived asymmetric two-center organocatalysts
作者:Takashi Ohshima、Tomoyuki Shibuguchi、Yuhei Fukuta、Masakatsu Shibasaki
DOI:10.1016/j.tet.2004.05.120
日期:2004.8
was used in phase-transfer alkylations and Michael additions to afford various optically active α-amino acid equivalents in up to 93% yield. Moreover, dramatic counter anion effects were observed in phase-transfer catalysis (PTC) for the first time, making it possible to further improve reactivity and selectivity. These findings validate the usefulness of three-dimensional fine-tuning of the catalyst
设计了一种新的高度通用的不对称两中心催化剂,酒石酸衍生的二铵盐(TaDiAS),并构建了包含70多种新的两中心催化剂的催化剂库。各种(S,S)-和(R,R在操作简单的反应条件下,使用常规和廉价的试剂,可以分别分别从l-酒石酸二乙酯和d-酒石酸二乙酯合成)-TaDiAS。TaDiAS用于相转移烷基化和Michael加成反应,以高达93%的收率提供各种旋光性α-氨基酸当量。此外,首次在相转移催化(PTC)中观察到了显着的抗衡阴离子作用,从而有可能进一步提高反应性和选择性。这些发现证实了对催化剂(乙缩醛,Ar和抗衡阴离子)进行三维微调以进行优化的有用性。使用简单的程序也可以回收和再利用催化剂。本不对称PTC已成功地应用于丝氨酸蛋白酶抑制剂铜绿蛋白酶298-A及其类似物的对映选择性合成。