A Palladium Complex as an Asymmetric π-Lewis Base Catalyst for Activating 1,3-Dienes.
A Palladium Complex as an Asymmetric π-Lewis Base Catalyst for Activating 1,3-Dienes.
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DOI：
10.1021/jacs.1c01420
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发表时间：
2021-03
影响因子：
15
通讯作者：
Ben-Xian Xiao;Bo Jiang;Ru‐Jie Yan;Jiangtao Zhu;Ke Xie;Xinyue Gao;Qin Ouyang;Wei Du;Yingchun Chen
中科院分区：
文献类型：
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作者：
Ben-Xian Xiao;Bo Jiang;Ru‐Jie Yan;Jiangtao Zhu;Ke Xie;Xinyue Gao;Qin Ouyang;Wei Du;Yingchun Chen
本文报道了钯(0)配合物能够以η-2的方式配位到1，3-二烯上，并通过回键将电子从d-轨道给予双键的空的反键分子轨道(π*)，从而显著提高了其最高占据分子轨道(HOMO)的能量。因此，根据葡萄酒学原理，非配位双键作为一个更具反应性的伙伴，可以直接攻击亚胺，提供形式的氢二烯基化反应的对映选择性。具有亲核基团的亚胺和1，3-二烯之间的化学选择性乙烯基加成/烯丙烷基化双官能化过程也是相容的，在初始烯加成后原位捕获形成的π-烯丙基钯物种。通过控制实验和密度泛函理论计算，阐明了这种π-Lewis碱催化模式，具有η2配位简单、乙烯基活化以及与共轭中性多烯和缺电子多烯都相容的特点。
Here we report that palladium(0) complexes can coordinate in a η2 fashion to 1,3-dienes and significantly raise the energy of their highest occupied molecular orbital (HOMO) by donating the electrons from the d-orbitals to the empty antibonding molecular orbitals of double bonds (π*) via back-bonding. Thus, the uncoordinated double bond, as a more reactive partner on the basis of the principle of vinylogy, can directly attack imines, furnishing a formal hydrodienylation reaction enantioselectively. A chemoselective cascade vinylogous addition/allylic alkylation difunctionalization process between 1,3-dienes and imines with a nucleophilic group is also compatible, by trapping in situ formed π-allylpalladium species after initial ene addition. This π-Lewis base catalytic mode, featuring simple η2coordination, vinylogous activation, and compatibility with both conjugated neutral polyenes and electron-deficient polyenes, is elucidated by control experiments and density functional theory (DFT) calculations.