CpRu/Bronsted Acid-Catalyzed Enantioselective Dehydrative Cyclization of Pyrroles N-Tethered with Allylic Alcohols
CpRu/Bronsted Acid-Catalyzed Enantioselective Dehydrative Cyclization of Pyrroles N-Tethered with Allylic Alcohols
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DOI：
10.1021/acs.orglett.0c00290
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发表时间：
2020-03-06
期刊：
影响因子：
5.2
通讯作者：
Kitamura, Masato
中科院分区：
文献类型：
--
作者：
Iwase, Shoutaro;Suzuki, Yusuke;Kitamura, Masato
阳离子CpRu/卤素/Bronsted酸杂化催化剂（R cat）具有轴向手性CI-Naph-PyCOOH配体（naph =萘基，py =吡啶），可以高效地脱水环化吡咯，构建1,2-融合-2-烯丙化吡咯，这是迄今为止尚未实现的。机理研究表明，氢和卤素键通过sigma-烯丙基中间体促进R， s - ru催化反应途径发挥关键作用，非对映体R，R- ru通过π -烯丙基中间体缓慢生成次要对映体。
A cationic CpRu/halogen/Bronsted acid hybrid catalyst (R cat) with the axially chiral CI-Naph-PyCOOH ligand (naph = naphthyl, py = pyridine) is highly efficient for dehydrative cyclization of pyrroles to construct 1,2-fused-2-allylated pyrroles that, so far, have not been achieved. The mechanistic study has implied that hydrogen and halogen bonds play a key role for facilitating the R,S-Ru-catalyzed reaction pathway via a sigma-allyl intermediate and that the diastereomeric R,R-Ru cat slowly gives the minor enantiomer via a pi-allyl intermediate.