Synthesis of chiral titanium-containing phosphinoamide ligands for enantioselective heterobimetallic catalysis
Synthesis of chiral titanium-containing phosphinoamide ligands for enantioselective heterobimetallic catalysis
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DOI：
10.1016/j.tet.2019.04.063
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发表时间：
2019-06-14
期刊：
影响因子：
2.1
通讯作者：
Michaelis, David J.
中科院分区：
文献类型：
--
作者：
Ence, Chloe C.;Walker, Whitney K.;Michaelis, David J.
合成了六个手性含钛膦酰胺配体。这些配体组装手性杂环钯钛配合物，使对映选择性的分子内烯丙基胺化与受阻胺亲核试剂，并实现选择性高达53%ee.Mechanism研究表明，可逆的对映体确定的C-N键形成步骤，这导致随着时间的推移，在% ee的反应逐渐增加。这些结果代表了一个罕见的对映选择性杂环化合物催化的例子，并表明这些新的配体可以在对映选择性过渡金属催化中找到广泛的应用。(C)2019爱思唯尔有限公司版权所有。
The synthesis of six chiral titanium-containing phosphinoamide ligands is discussed. These ligands assemble chiral heterobimetallic Pd-Ti complexes, enable enantioselective intramolecular allylic aminations with hindered amine nucleophiles and achieve selectivity up to 53% ee. Mechanistic studies demonstrate the reversibility of the enantio-determining C-N bond forming step, which leads to a gradual increase in the % ee of the reaction over time. These results represent a rare example of enan-tioselective heterobimetallic catalysis and suggest that these new ligands could find broad application in enantioselective transition metal catalysis. (C) 2019 Elsevier Ltd. All rights reserved.