Mechanistic Insights into a Chiral Phosphoric Acid-Catalyzed Asymmetric Pinacol Rearrangement
Mechanistic Insights into a Chiral Phosphoric Acid-Catalyzed Asymmetric Pinacol Rearrangement
复制标题
DOI：
10.1021/acs.joc.8b02812
复制
发表时间：
2018-12-07
影响因子：
3.6
通讯作者：
Rodriguez, Juan B.
中科院分区：
文献类型：
--
作者：
Falcone, Bruno N.;Grayson, Matthew N.;Rodriguez, Juan B.
第一个催化的对映选择性频哪醇重排是由Antilla及其同事在2010年报道的。该反应由手性磷酸催化，并导致高水平的对映选择性（高达96%ee）。本研究利用密度泛函理论来探讨这一重要反应的立体选择性的机理和起源，并解释不同催化剂之间选择性的差异。在[1，2]-芳基位移的优选活化模式下，观察到中间体吲哚醇与催化剂中的磷酸根之间的OH中心点中心点O氢键以及吲哚与磷酸根之间的CH中心点O氢键。在主要过渡态，CH中心点O相互作用较强，有助于高水平的对映选择性。发现更大体积的催化剂（TRIP）阻碍关键CH中心点O相互作用的形成，导致较低水平的对映选择性。
The first catalytic enantioselective pinacol rearrangement was reported by Antilla and co-workers in 2010. The reaction was catalyzed by a chiral phosphoric acid and resulted in high levels of enantioselectivity (up to 96% ee). The present study uses density functional theory to investigate the mechanism and origins of stereoselectivity of this important reaction and to explain the difference in selectivity between different catalysts. An OH center dot center dot center dot O hydrogen bond between the intermediate indolyl alcohol and the phosphate group from the catalyst together with a CH center dot center dot center dot O hydrogen bond between the indole and the phosphate group were observed in the preferred activation mode for the stereodetermining [1,2]-aryl shift. A stronger CH center dot center dot center dot O interaction in the major transition state was found to contribute to the high levels of enantioselectivity. A more bulky catalyst (TRIP) was found to impede the formation of the key CH center dot center dot center dot O interaction, leading to lower levels of enantioselectivity.