Organometallic titanocene complex as highly efficient bifunctional catalyst for intramolecular Mannich reaction
Organometallic titanocene complex as highly efficient bifunctional catalyst for intramolecular Mannich reaction
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有机金属二茂钛配合物作为分子内曼尼希反应的高效双功能催化剂
DOI：
10.1002/aoc.4925
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发表时间：
2019
影响因子：
3.9
通讯作者：
Gao Ziwei
中科院分区：
文献类型：
--
作者：
Wang Yunyun;Jian Yajun;Wu Ya;Sun Huaming;Zhang Guofang;Zhang Weiqiang;Gao Ziwei
Cp2TiCl2与羧酸配体组装成具有Lewis酸性金属钛和Brnsted酸性COOH两个催化中心的双功能催化剂，对合成2-芳基-2，3-二氢喹啉-4(1H)-酮的分子内Mannich反应表现出较高的催化活性。用单X-射线热重-质谱法对双功能催化剂Cp_2Ti(C_8H_4NO_6)_2进行了测定，并对其催化行为进行了研究。特别是，用休眠的库姆掩盖Brnsted酸性COOH催化中心，大大降低了反应产率，表明两个催化中心协同工作，保持了较高的催化效率。
Bifunctional catalysts bearing two catalytic sites, Lewis acidic organometallic titanocene and Brønsted acidic COOH, have been assembledin situfrom Cp2TiCl2with carboxylic acid ligands, showing high catalytic activity over an intramolecular Mannich reaction towards synthesis of 2‐aryl‐2,3‐dihydroquinolin‐4(1H)‐ones. The determination of the bifunctional catalyst Cp2Ti(C8H4NO6)2was elucidated by single X‐ray HR‐MS and investigation of catalytic behavior. In particular, masking the Brønsted acidic COOH catalytic site with dormant COOMe lowered the reaction yield greatly, indicating that two catalytic sites work together to maintain high catalytic efficiency.