Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany.
Angew Chem Int Ed Engl. 2017 Jul 10;56(29):8393-8397. doi: 10.1002/anie.201704184. Epub 2017 Jun 21.
A manganese alkyl complex containing a chiral bis(oxazolinyl-methylidene)isoindoline pincer ligand is a precatalyst for a catalytic system of unprecedented activity and selectivity in the enantioselective hydroboration of ketones, thus producing preparatively useful chiral alcohols in excellent yields with up to greater than 99 % ee. It is applicable for both aryl alkyl and dialkyl ketone reduction under mild reaction conditions (TOF >450 h at -40 °C). The earth-abundant base-metal catalyst operates at very low catalyst loadings (as low as 0.1 mol %) and with a high level of functional-group tolerance. There is evidence for the existence of two distinct mechanistic pathways for manganese-catalyzed hydride transfer and their role for enantiocontrol in the selectivity-determining step is presented.
一种含手性双(恶唑啉基甲基亚氨基)茚满钳形配体的锰烷基配合物，是在酮的对映选择性硼氢化反应中具有空前活性和选择性的催化体系的前催化剂，因此以优异的产率（高达大于 99%ee）制备有用的手性醇。它适用于芳基烷基和二烷基酮在温和的反应条件下还原（TOF 在-40°C 下大于 450 h）。这种丰富的地球基础金属催化剂在非常低的催化剂负载（低至 0.1mol%）下运行，并具有高水平的官能团耐受性。有证据表明存在两种不同的锰催化氢化物转移的机理途径，并且它们在决定选择性的步骤中对映控制的作用被提出。
